Revision of Iberian species of the genus Merodon ( Diptera : Syrphidae )

This study is a revision of the Iberian Merodon Meigen, 1803 species, including an illustrated key, a discussion of taxonomic characters and a morphological diagnosis for all included species. Descriptions are provided for nine new species: M. antonioi sp. n., M. arundanus sp. n., M. cabanerensis sp. n., M. crypticus sp. n., M. hurkmansi sp. n., M. legionensis sp. n., M. longispinus sp. n., M. luteihumerus sp. n. and M. quercetorum sp. n. The taxon M. escorialensis Strobl, 1909 is redescribed and lectotype is designated. Lectotypes are designated for four taxa: M. albifrons Meigen, 1822; M. spinipes obscuritarsis Strobl in Czerny & Strobl, 1909; M. spicatus Becker, 1907; and M. spinipes grossus Gil Collado, 1930. Three varieties are redefined and considered as valid species: M. obscuritarsis Strobl in Czerny & Strobl, 1909 (as var. of spinipes); M. grossus Gil Collado, 1930 (as var. of spinipes); M. unicolor Strobl in Czerny & Strobl, 1909 (as var. of aeneus). The following new synonymies are proposed: M. affinis Gil Collado, 1930 syn.n. (= junior synonym of M. longicornis Sack, 1913); M. lusitanicus Hurkmans, 1993 syn.n. (= junior synonym of M. serrulatus Wiedemann in Meigen, 1822); M. andalusiacus Paramonov, 1929 syn.n., M. bolivari Gil Collado, 1930 syn.n., M. hispanicus Sack, 1931 syn.n. (= all three are junior synonyms of M. unguicornis Strobl in Czerny & Strobl, 1909); M. spicatus Becker, 1907 syn.n. (= junior synonym of M. chalybeus Wiedemann in Meigen, 1822); M. fuerteventurensis Barkemeyer, 2002 syn. n. (= junior synonym of M. obscuritarsis Strobl, 1909); and M. spinipes grossus (Gil Collado, 1930) syn.n. (= junior synonym of M. albifrons Meigen, 1822). Status of M. serrulatus Wiedemann in Meigen, 1822 is revised. Four species: M. longicornis Sack, 1913, M. pumilus Macquart, 1849, M. ottomanus Hurkmans, 1993 and M. segetum (Fabricius, 1794) are new for the Iberian Peninsula. Male genitalia are illustrated for all the species and a key of the 34 Iberian species (+ M. hurkmansi sp. n.) for males and females (except for the unknown female of M. longispinus sp. n.) is appended. Distribution and biological data for the Iberian species are also included. A brief zoogeographic discussion is also presented. The level of endemism of genus Merodon on the Iberian Peninsula is extremely high (almost 50%).


INTRODUCTION
The Old World genus Merodon Meigen, 1803 (Diptera: Syrphidae) is one of the most widespread in the Mediterranean region and the second largest genus of European Syrphidae with more than 50 European species (Speight, 2004).It is distributed over the Palaearctic and Ethiopian regions, with most species occurring on the steppes of eastern Europe and beyond, with over 60 species recorded from Turkey, for example (Siribiyic, pers. com.).
Merodon belongs to the tribe Merodontini (Edwards, 1915) and its distinctive characteristic is a triangular projection beneath the distal part of the hind femora and vein R4+5 curving deeply into cell R5.Most species are insufficiently treated in taxonomic works, and the lack of male genitalia descriptions increases the difficulty for their identification.The morphological intra-specific variability is well known in some species such as M. equestris (Fabricius, 1794) and M. aureus Fabricius, 1805 which show a wide range of colour varieties, or M. tricinctus Sack, 1913 which presents a high intra-specific variability in the anterior lobe of the surstyle of the male genitalia (Popov, 2000).
The biology of the Merodon species is poorly known and the larval cycle of all known species develops underground in bulbs or tubercles of monocotyledonous species in Liliaceae and Amarillidaceae (Seguy, 1961, Hurkmans, 1993).M. equestris larvae live in bulbs of commonly used garden plants such as Amaryllis, Hyacinthus and Narcissus (Rotheray, 1994) and in some cases, can be considered an horticultural pest (Stubbs & Falk, 2002).
Large Merodon species can be confused with bumblebee mimics of various genera, and small and elongated species could be also confused with Eumerus Meigen, 1822.The adult flies are mostly found near the ground, flying among the vegetation, close to the ground or resting on stones or bare soil.Adults of the various species of Merodon appear to have a preference for flowers of Apiaceae (Hurkmans, 1993).
Up until now, the only comprehensive study of the Palaearctic species of this genus was that of Hurkmans (1993), a revision of 61 species.Radenkovi et al. (2002) established new synonyms and clarified the taxonomy of this group after the examination of type material of the ruficornis group of species.
In the Iberian Peninsula 30 species of Merodon were recorded (Marcos-García et al., 2002) with 23% of the species being endemic.Data on adult habitats, visited flowers, flight periods and Spanish distributions are provided in Marcos-García (1985a, b, 1989, 1990a, b) but the Iberian Merodon species had not been comprehensively revised before.The high number of species and endemism in the Iberian Peninsula, the apparent similarities between species and deficiencies in the original description of some species and the lack of an integrated study, stimulated us to delve into the knowledge of the taxonomy and distribution of the Iberian species of Merodon to facilitate future studies on this genus.The present comprehensive study, in which eight new species are described, brings the total to 34 Iberian Merodon species plus M. hurkmansi sp.n. from Algeria.Whereas the latter does not presently belong to the Iberian fauna, it has also been included in this revision to facilitate its separation from M. albifrons Meigen, 1822 and considering the possible discovery of this species in the Iberian Peninsula due to the proximity and the high level of connection between Spain and this African country.

MATERIAL AND METHODS
The systematic portion of the present study is based on the examination of all the available material of this genus previously cited in bibliography or unpublished works and belonging to private collections.Type specimens of some species have also been studied.
To avoid unnecessary repetitions, the collection is only mentioned when the studied material does not belong to the CEUA.
The characters used in the key, descriptions, and drawings employ the terminology established by Thompson (1999) and those relating to male genitalia are those employed by Hurkmans (1993) and Doczkal (1996).Colour characters are described from dry mounted specimens.Unless otherwise stated in the sections "Material examined", the specimens under study were collected by sweeping net.Some specimens were captured using Malaise traps (MT), dried after preservation in ethanol and mounted with entomological pins in the course of the study.
To study the male genitalia, specimens were relaxed and the genitalia were extracted with an insect pin with a hooked tip.The genitalia were stored in microvials containing glycerol.
Drawings were made with a FSA 25 PE drawing tube attached to a binocular microscope.Measurements were taken with an eyepiece graticule or micrometer.

Abbreviations used in key, diagnosis and description
cx -posterior part of mid coxa (Figs 1-4); bf -relation between distance from top of basoflagellomere and most prominent point of pedicel (Fig. 5: x) and width of basoflagellomere at level of base of arista (Fig. 5: y); pa -posterior anepisternum .

Male genitalia
AL -anterior surstyle lobe; C -cercus; EA -ejaculatory apodeme; IL -interior accessory lobe of posterior surstyle lobe; L -532 For each new species we provide a short description and figures of adult morphological data.Diagnoses comprise accounts of unique characters relative to the species considered here and also combinations of characters that enable taxa to be distinguished and recognised.Keys are also provided to enable identification of adults.Under each species additional details of material examined, geographical distribution, biological data and institutions where holotypes may be studied are given.In the studied material, the country is only indicated if it is not Spain.World distribution is compiled from Peck (1988), Hurkmans (1993), Dirickx (1994), Marcos-García et al. (2002), Speight (2004) and van Veen (2004).
A summary of the world distribution and known biological data, such as preference of habitat and visited flowers (from Speight, 2004) is included in the treatment of each species, emphasizing the new data in bold.A map of the Iberian distribution is also included for each species (black circles refer to examined material and white squares unexamined material).
In the examined material, the locality is not indicated when absent in the original paper.

KEY FOR IBERIAN SPECIES OF GENUS
Iberian distribution.Sistema Central of Spain (Fig. 244).Range.through central Europe from Germany, the Czech Republic and the Alps (France, Switzerland, Austria) to Hungary and Romania and on to the Ukraine and southern Russia; in southern Europe from mountainous parts of Portugal and Spain eastwards to Italy, Albania, the former Yugoslavia and Greece and on to Turkey and round the Mediterranean (Lebanon) into North Africa (Morocco), including Mediterranean islands e.g.Crete.

Female
Similar to the male except for the following characteristics: Basoflageromellere and pedicel with more extended red ventral colouration.Ocellar triangle equilateral.Frons shiny, white dusted laterally and covered with yellowishwhite hairs anteriorly reclined.Mesonotum and scutellum with white hairs.Hind tibia without apical process.
Diagnosis.Species with hairy cx and reduced hairs on pa, it belongs to the geniculatus group characterized by a hind trochanter with a blunt thorn, usually covered with hair-tuft (as in Fig. 61); bf = 1.5; medium sized (12.6-14.0mm) species; thorax covered with pale hairs.M. antonioi sp.n. is fairly similar to M. crypticus sp.n. and M. escorialensis but can be easily distinguished by the following morphological characteristics: pilosity of the vertical triangle completely white in M. escorialensis and M. antonioi sp.n. and with a tuft of dark hairs in M. crypticus sp.n.; mesonotum with uniform yellowishwhite hairs on dorsal surface in M. escorialensis and M. antonioi sp.n. and with one trasverse band of black pilosity at the level of wing insertion in M. crypticus sp.n.; hind tibia with a blunt apico-lateral process in M. escorialensis (Fig. 61) and M. antonioi sp.n. and sharp processes in M. crypticus sp.n. (Fig. 62); posterior surstyle lobe rounded in M. crypticus sp.n. (Fig. 162) and acute in M. escorialensis (Fig. 159) and M. antonioi sp.n. (Fig. 161); C in M. escorialensis with two apical prominences of similar size (Fig. 71), with a strongly developed anterior prominence in M. antonioi sp.n. (Fig. 72) and a much developed the posterior one in M. cryticus sp.n. (Fig. 73).
Variability.The colour of legs can vary from almost all tarsi pale to predominantly dark tarsi, especially dorsally.Etymology.The name antonioi refers to the first name of the collector of the type serie specimens, Antonio Ricarte.
Biology.Preferred environment: Open areas with Fraxinus angustifolia close to seasonal rivers.Adults were caught resting on the rocks of a dry river bed.Period of flight: September.
Iberian distribution.Cabañeros National Park (Montes de Toledo) in the Centre of Spain.Adults have been caught in the valley of the river Gargantilla (Fig. 244). Range.Spain.

Merodon arundanus sp. n.
Figs 89, 122-125 Male Head.Antennae dark brown; basoflagellomere 1.1 times longer than wide; apex acute.Face and frons black, white dusted and with yellowish-white hairs.Oral margin bare and shiny black.Vertical triangle big, isosceles with yellow hairs in anterior and posterior part and with a tuft Abdomen.Dark, oval and longer than mesonotum.Tergite II with two reddish lateral spots; tergites II-IV with a dusted transversal band.Sternites entirely black.Abdomen completely covered with dense, long reddish hairs.
Male genitalia.PL rounded in lateral view, with a small notch on upper margin (Fig. 122).Surstyle margin straight till the elevation of the long and strong marginal thorn (Figs 122,123).AL with a wide excavated circular area limited by a very long sickle-shaped thorn and apical prominence twisted and pointed medially (Fig. 123).C convex, without prominences (Fig. 122).Hypandrium with thecal ridge strongly folded (Fig. 124).

Female
Unknown.
Diagnosis.Big (14.5-16.5 mm), stocky species with hairy cx and reduced hairs on pa; bf = 1.1; body covered with dense, reddish hairs, erect on tergites; tergites III, IV with narrow greyish pollinose stripes.This species is fairly similar to M. tricinctus but can be easily distinguished by the long, erect, reddish hairs on tergites, strongly folded theca and the extremely long thorn on the surstyle margin of the genitalia.Etymology.The name arundanus is derived from Arunda, the Latin name of the mountains range of the Sierra de Grazalema and Ronda (Spain) where the type specimens were collected.
Biology.Preferred environment: Open area at the top of Abies pinsapo forest.Period of flight: April.
Iberian distribution.Grazalema National Park, mountainous area in the South of the Iberian Peninsula with the highest level of annual precipitation (2,132 mm) in Spain (Fig. 245).
Range.Spain.M. avidus (Rossi, 1790) is the most frequent and widely distributed of a group of closely related species (Speight, 2006).This group has been the subject of taxonomic debates due to its great morphological variation, resulting in up to 24 known synonyms for M. avidus (Hurkmans, 1993).There is no key in which all known European members of this group of species are included and females, in particular, can be extremely difficult to separate.In a recent study of allozyme and morphological variability in populations of the M. avidus taxon, two cryptic taxa were identified, Mediterranean Merodon avidus A and mountainous Merodon avidus B species based on the diagnostic species-specific alleles at Idh-2 and Aat loci and diagnostic morphological characters (Milankov et al., 2001).
There are specimens published as M. avidus before 2001, that were not posible to examine or were unavail- Diagnosis.Medium sized (12.3-14.6 mm), slender species with relatively short body hairs, olive-brown groundcolour; cx bare and pa with reduced hairs; tergites III, IV always with whitish pollinose stripes; colour of tergites III, IV very variable, from dark, to almost completely red (avidus group); basoflagellomere elongated, bf = 1.4 (Fig. 17); tergite II always with a pair of whitish pollinose spots, from clear to almost indistinct (Fig. 21); tibiae usually pale; tergites II, III usually with reddish lateral spots; male genitalia: PL square-form; AL oval; small hairy protuberance between surstyle lobes; hypandrium with L, apical part narrow; S elongated .Diagnosis.Extremely similar to previous species, except basoflagellomere slightly less elongated, fm = 1.3 (Fig. 16); tergite II shiny, unpollinose (Fig. 22); hind tibiae partly dark; tergite III usually without reddish lateral spots; no established differences in male genitalia characters between these two taxa.Iberian distribution M. avidus A. Sistema Central and Sierra Montseny (Northeast of Spain) (Fig. 245).

Male
Head.Antennae black; basoflagellomere rounded, approximately as long as wide and as long as scape and pedicel together; distance between antennal pit and top of basoflagellomere twice as long as the distance between pit and base of basoflagellomere.Front and occiput dull black, face covered with long grey hairs reclined to the medium line on face.Vertical triangle isosceles, black with long pale hairs, except some black ones on the ocellar area.Eyes with white hairs; ocellar triangle equilateral.Length of eye contiguity line similar to the distance between two ocelli.
Thorax.Mesonotum and scutellum dark with metallic luster and covered with erect red-yellowish hairs.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellow hairs.Wings pale-greyish with dark veins.Dorsal and ventral calypters pale yellow with dark margins.Halteres with pale pedicel and yellow and dark capitulum.Legs completely dark and covered with yellow hairs.Hind tibiae slightly nicked in the ventral part.Hind trochanter without thorn.Ventral part of tarsi with dense red hairs.
Abdomen.Oval, with the widest part in the second tergite.Black with metallic luster.Tergites II-IV with unclear marks of pubescence; covered with yellowish hairs except posterior half of second and third tergites 545 with black adpressed hairs.Sternites black with erect, yellowish hairs.
Male genitalia.AL not visible in lateral view, but developed and containing a medially pointed prolongation covered with dense short hairs (Fig. 134).PL very narrow on the apical half.T in characteristic shape (Figs 135,136).EA large (Fig. 135).S curved posteriorly (Fig. 135).

Female
Similar to the male except for sexual dimorphism and the following characteristics: frons black, dull, covered with yellowish hairs, anteriorly reclined and with a median longitudinal groove from anterior ocellus to lunule.Vertical triangle black with long, black hairs.Ocellar triangle equilateral.Transversal abdominal lines of pubescence inconspicuous.Range.Spain.Merodon chalybeus was described from a single specimen.In the Meigen collection there is one specimen with original name label and corresponding data.We accept this specimen as the holotype: female "var.chalybea / Lusitania / Hoffmannsegg S. / Type" (Portugal) (MFNB).

Merodon chalybeus Wiedemann in Meigen, 1822
M. spicatus was described from an unspecified number of males and females.There are two type specimens (syntypes) found in two Museums; the designation of lectotype was based on more comprehensive data on specimen in KBIN collection.Lectotype (designated here): male Diagnosis.Small (6.6-8.0 mm) species with hairy cx and many hairs on pa, thorn on hind trochanter in male (aureus group); basoflagellomere reddish to brown; upper (and lower) part of eyes dark haired; body hairs not so dense as in other species in the aureus group, hairs whitish-grey to yellowish-grey; mesonotum usually at least near wing bases with black hairs; mesonotum and tergites with dark-olive tegument; tergite II on posterior 1/3 and central parts of tergite III (except pale stripes on the middle) black haired; tergites II, III with small pollinose stripes; legs dark, tibiae at both ends and tarsi in part can be paler; apical part of hind femora with black hairs; male genitalia similar to M. aureus: AL undeveloped with straight ventral margin; PL rounded apically; hypandrium narrow, elongated and sickle-shaped; S reduced .
Variability.This species can be very variable in size ( 4 Iberian distribution.Mountains of the Sistema Central of Spain (Fig. 246).
Range.Spain, Portugal and southern France round the Mediterranean to parts of the former Yugoslavia and on to North Africa (Morocco).Diagnosis.Big (17-23 mm), bumble bee-like species with long and dense body hairs; cx bare, pa with reduced hairs; hind femora thickened; bf = 1.8 (Fig. 6); usually yellowish-white haired species with stripe of black hairs between wing basis, and red-yellow hairs on tergites III, IV; tergites with pollinose stripes covered with hairs; legs black; male genitalia: PL square-shape, with small lateral bulge; AL large, extensively covered with dense short hairs; hypandrium with small L; S elongated .

Merodon clavipes (Fabricius, 1781)
Variability.The colour of hairs on body can be variable; based on that fact few varieties were described (for more see: Hurkmans, 1993).
Abdomen.Dark, oval and longer than mesonotum.Tergites II-IV black with white pruinose transverse bands interrupted in the middle on tergites II and III; posterior margin of tergites pale; tergite II with pale antero-lateral margin; tergites covered with adpressed hairs of the same colour as the tegument.Sternites, pale spots of tergite II and lateral margin of all tergites covered with long pale hairs.Sternite I dark anteriorly and pale posteriorly; sternites II and III pale; sternite IV and posterior ones dark brown.

Female
Similar to the male except for the following characteristics: Antennae brown with pale ventral surface.Frons shiny, white dusted laterally and covered with yellowishwhite hairs anteriorly reclined.Ocellar triangle equilateral, covered with black hairs.Hind tibia without apical process.
Diagnosis.Species with hairy cx and reduced hairs on pa, hind trochanter with blunt thorn, usually covered with tuft of hairs (Fig. 62) (geniculatus group); bf = 1.1-1.2(Figs 69, 106); medium sized (10.6-14.0mm) species, with a stripe of black hairs between wing bases; hind tibia with apico-medial spur (Fig. 60); C with two distinct apical prolongations (Fig. 70).For more details, see diagnosis of M. antonioi sp.n.Etymology.The name crypticus is derived from the same Latin word that refers to the newly discovered cryptic species among M. escorialensis specimens.
Biology.Preferred environment: Open ground areas of the high mountains belonging to the Spanish Eurosiberian region.Period of flight: July-September.
Variability.Black hairy stripe on scutum can be absent; basoflagellomere can be from orange to darkbrown; tibiae and tarsi are usually orange, but tibiae can have dark parts and tarsi can be darkened dorsally.Colour of tergites III, IV is very variable, from dark, to almost completely reddish.Additional published records.Hurkmans (1993).Range.Spain, southern France (and Corsica), southern Italy (and Sicily); Northwest Africa (Algeria, Morocco); western Mediterranean species.Diagnosis.Big (17-23 mm), bumble bee-like species with long and dense body hairs; cx hairy, pa with reduced hairs; apical prolongation of hind tibiae long and curled (Fig. 57); hind tibiae with large central bulge (Fig. 57); male genitalia: PL with rounded top; surstyle margin more or less straight, until the marginal thorn; marginal thorn small, bifid; AL with long apical extension pointed medially; C large, triangular; hypandrium with folded thecal ridge; S with large, oval apical part .

Merodon equestris (Fabricius, 1794)
Variability.Body hairs can be very variable, from specimens with almost completely pale hairs to specimens with black haired posterior half of scutum and tergite III; some varieties were described based on this polymorphism.Range.Fennoscandia south to Iberia and the Mediterranean, including N Africa; from Ireland eastwards through much of Europe into European parts of Russia; also in Japan; in North America from British Colombia south to California.Human activities have resulted in the introduction of this species to parts of the world outside its natural range, including New Zealand.Within Europe its range has almost certainly been expanded due to human activity and it is doubtful, for instance, that this species reached either Britain or Ireland unaided by man (Speight, 2006).M. escorialensis was described from the three syntypes, as variety of M. geniculatus.Marcos-García (1989) concluded that it must be considered as a distinct species.But the designation of neotype (Marcos-García, 1989) was incorrect, because of currently recognised syntypes from the Strobl collection.In this paper we designate the lectotype.Lectotype (designated here): male "geniculatus v. escorialensis / Escorial, Rd" (Spain) (NMBA).Paralecto- This species is re-described because previous descriptions contain characters from three cryptic species (M.antonioi sp.n., M. crypticus sp.n. and nominated species).

Male
Head.Antennae brown; basoflagellomere 1.2 times as long as pedicel, upper margin slightly concave, apex acute.Face, frons and occiput black covered by dense white pubescence and long white hairs.Oral margin bare and lustrous black.Ocellar triangle isosceles.Eyes with white hairs; vertical triangle with white erect pilosity.
Thorax.Mesonotum and scutellum dark green with metallic luster and covered with erect pale-yellow hairs.Some specimens have a group of black setae at wings base.Five dusted longitudinal stripes can be visible from posterior view.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellowish-white hairs.Wings pale-greyish with dark veins.Dorsal and ventral calypters pale-yellow.Halteres with yellow capitulum and pale-brown pedicel.Femora dark-brown with pale apical part.Fore and mid tibiae yellow in basal part in a variable extension with distal dark end; hind tibiae yellow with dark median band and with a blunt apico-medial process.Tarsi dark, with the two first tarsomeres partly pale.Hind trochanter with a distinct rounded thorn covered with long, dense hairs.Legs with pale hairs except some black adpressed ones on the dorso-apical part of the hind femora.
Abdomen.Dark, oval and longer than mesonotum.Tergites II-IV black with white pruinose transverse band interrupted in the middle on tergites II and III; posterior margin of tergites III and IV pale; tergite II with pale antero-lateral spots.Tergites covered with adpressed hairs of the same colour as the tegument; long pale hairs on sternites, on pale spots of tergite II and on lateral margin of all tergites.Sternite I dark anteriorly and pale posteri-orly; sternites II and III pale; sternite IV and posterior ones dark brown.

Female
Similar to the male except for the following characteristics: Antennae brown with pale ventral surface.Frons shiny, white dusted laterally and covered with yellowishwhite hairs anteriorly reclined.Ocellar triangle equilateral, covered with black pilosity.
Diagnosis.Species with hairy cx and reduced hairs on pa, hind trochanter with blunt thorn, usually covered with tuft of hairs (Fig. 61) (geniculatus group); bf = 1.2 (Figs 68, 108); medium sized (11.0-13.3mm) species, with pale haired scutum, usually with few black bristles near wing bases; hind tibia with apico-medial spur (Fig. 61); C with two distinct apical prolongations (Fig. 71).Fore more details see diagnosis of M. antonioi sp.n. lateral view;anterior view;lateral view;  Range.Spain (from Cantabrian mountains southwards into much of central Spain).Diagnosis.Big (13.3-14.0mm), bumble bee-like species related to M. equestris, with long and dense yellowish body hairs; cx hairy, pa with reduced hairs; apical prolongation of hind tibiae not so long and straight (Fig. 58); hind tibiae with small central bulge (Fig. 58); male genitalia similar to that of M. equestris: PL with rounded top and anterior acute excavation; surstyle margin slightly rounded (more or less straight in M. equestris); marginal thorn larger, with bigger inner tooth than in M. equestris; AL with long apical extension pointed medially; C triangular, but smaller than in M. equestris; hypandrium with folded thecal ridge; S with large, oval apical part .Diagnosis.Small (8.0-10.6)species with hairy cx and many hairs on pa, short rounded abdomen, and thorn on hind trochanter of male, related to aureus group; antennae usually dark, pedicel as long as basoflagellomere (Figs 34,35); hairs on eyes from whitish to greyish; scutum punctured medially, usually with two narrow central and two broader lateral pollinose stripes; legs dark with pale knees, tibiae at both ends and tarsi (at least ventrally); tergites with very rough punctures, especially on tergites II, III, on dark haired parts; tergites II-IV with pale pollinose stripes covered with pale hairs; tergite IV with adpressed golden-greyish hairs in clear contrast to black haired central parts of tergite III (and II); male genitalia: PL pointed towards top; AL undeveloped; C rounded; hypandrium straightened on the central acute part; S small .
Range.Southern France, Portugal, Spain, Italy, southern parts of the former Yugoslavia, Bulgaria, Turkey, Israel and N Africa (Algeria, Morocco); Mediterranean islands: Balearics, Corsica, Malta.

Male
Head.Antennae brown, pale in ventral part; basoflagellomere 1.4 times longer than wide, apex acute, dorsal margin straight.Face and frons black, white dusted and with yellowish-white hairs.Oral margin black lustrous, bare.Vertical triangle isosceles with yellow hairs.Ocellar triangle isosceles.Eye contiguity line in males as long as the distance between the anterior and posterior ocelli.Occiput black with yellow hairs.
Thorax.Mesonotum and scutellum dark-green with metallic luster and covered with erect yellow hairs and some black ones on wing bases.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellowish hairs.Five longitudinal dusted bands visible in posterior view.Wings pale-greyish with dark veins.Dorsal and ventral calypters pale yellow.Halteres yellow, slightly dark.Femora dark brown with pale apex.Fore and mid tibiae yellow in basal part with distal dark end; hind tibia yellow with dark median band and with a short and blunt apico-medial process; mid femora with ventral short black bristles.Tarsi darkened, except for three basal Abdomen.Dark, oval and longer than mesonotum.Tergite I completely black; tergite II with red antero-lateral spots; tergites III and IV black with large white pruinose transverse stripes interrupted in the middle; stripe on tergite IV at least one fourth of its length; all tergites covered with adpressed hairs of same colour than tegument.Sternites, anterior corner of tergite II and lateral margin of all tergites with long pale hairs.Sternites mainly dark brown.
Etymology.The name hurkmansi is dedicated to Willem Hurkmans in recognition of his long-term work on Merodon species.
Biology.Period of flight: April.

Male
Head.Antennae brown; basoflagellomere pale and 1.2 times as long as pedicel; upper margin straight; apex acute.Face and frons shiny black covered with long white-yellow hairs.Oral margin black lustrous, bare.Occiput covered by white pubescence and long white hairs.Vertical triangle equilateral and with white hairs.Eyes with white hairs on the low surface and black on the upper part.

558
Thorax.Mesonotum and scutellum dark green with metallic luster covered with erect yellow hairs.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellowish-white hairs.Wings pale-greyish with dark veins.Dorsal and ventral calypters pale yellow.Halteres with yellow pedicel and brown capitulum.Femora dark brown with pale colour apically and with long anterior white hairs and short posterior black reclined hairs.Tibiae yellow, occasionally with dark traces on the middle.Tarsi yellow except two last tarsomeres dark.Tibiae and tarsi with yellow hairs and some black ones.Hind trochanter with an inner bifid thorn.
Abdomen.Oval, approximately as long as mesonotum; dark green with metallic luster and covered with adpressed yellowish hairs.Second and third tergites bearing a pair of dusted transversal spots.Sternites black with long pale hairs.
Male genitalia.Similar to M. aureus.AL is undeveloped with straight ventral margin; PL is rounded on the apex with long hairs and parallel margins (Fig. 190).C elongated, without prominences.Hypandrium narrow, elongated and sickle-shaped; S reduced .

Female
Similar to the male except for the following characteristics: Frons shiny and covered with yellowish-white hairs; two narrow longitudinal bands of white pubescence near the eye margins.Ocellar triangle with black hairs.Hind trochanter without thorn.Abdomen shiny black with a pair of white dusted bands on the tergites II, III and IV.In the tergite II these spots are subparallel to the margins of the tergite and in the tergites III and IV are oblique.
Etymology.The name legionensis is derived from Legio VII, the Roman name of León, the Spanish province where the first specimens of this species were collected.Merodon affinis: holotype (original designation): female "Escorial" (Spain) (MNMS).[Holotype is slightly damaged, without antennae; fortunately the drawing of the head from the original description contains the shape of antenna, which fits M. longicornis Sack; this long antenna clearly separated this species from all others in the genus; the other morphological characters also fit M. longicornis].

Merodon longicornis Sack, 1913
Diagnosis.Medium sized to small (7.3-10.6 mm), slender species; cx bare and pa with reduced hairs; basoflagellomere very long, bf = 2.2 (Fig. 5); face, pleurae and legs with whitish hairs, vertex (and frons in female) with black hairs; scutum with stripe of black hairs between wing bases and four pollinose longitudinal stripes; knee, tibiae at both ends and tarsi, at least ventrally, paler; tergites black in male, tergites II, III in female completely or partly red; tergites II-IV with clear white pollinose stripes; male genitalia: PL square-shaped, with ventral triangular prominent part, in lateral view; recess between surstyle lobes large and deep; AL medium sized, oval, covered with dense short hairs; hypandrium with small L; S elongated .
Variability.Frons in female with many or only a few black hairs; tergites II, III in female from partly to completely red.Range.Former Yugoslavia, Greece, Turkey, Ukraine, southern Russia, Lebanon, North Africa.These are the first data from the Iberian Peninsula.
Thorax.Mesonotum dark, lustrous and covered with erect yellow hairs.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellowish-white hairs.Wings pale-greyish with darkened veins.Dorsal and ventral calypters pale yellow.Halteres yellowishbrown.Femora dark-brown, paler apically.Fore and mid tibiae yellow, with black apical third; hind tibiae yellow with a black central band.Fore tarsi with yellow basal tarsomeres and darker apical ones.Hind trochanter with a very long thorn, wider and rounded on its top.Femora with long white hairs.
Abdomen.Oval, approximately as long as mesonotum; dark lustrous and covered with long adpressed dark hairs.Tergites II-IV bearing a pair of dusted transversal spots.Tergite II with red antero-lateral spots.Sternites black covered with long pale hairs.

Female
Unknown.
Diagnosis.Big species (14 mm) with hairy cx and reduced hairs on pa, hind trochanter with blunt thorn, usually covered with tuft of hairs (geniculatus group); M. longispinus sp.n. can be easily distinguished from other species of the geniculatus group by the extremely long thorn on the hind trochanter (Fig. 60); basotarsomere of hind leg with medial incision on central part (Fig. 64); hind femora swollen, curved basally (Fig. 60); basoflagellomere (Fig. 66) reddish (bf = 1.2); eyes pale haired; tibiae pale with dark central part; tarsi pale, except darkened two tarsomeres; body hairs pale; tergites black; tergite II with reddish lateral spots; tergites III, IV with pollinose stripes.
Etymology.The name longispinus is derived from the very long tubercle on the hind tibia.
Biology.Preferred environment: Open ground close to rivers on mountains in the south of Spain.Flowers visited: Lavandula latifolia.Period of flight: September.

Merodon luteihumerus sp. n.
Figs 74,77,[194][195][196][197] Male Head.Antennae short and completely yellow; basoflagellomere slightly longer than pedicel; apex rounded.Face and frons black, white dusted and with yellowish-white hairs.Oral margin yellowish and black, bare and lustrous.Vertical triangle isosceles with yellowish hairs; anterior angle with dense white pubescence and white hairs anteriorly reclined.Ocellar triangle isosceles.Eye contiguity line in males as long as the distance between the two posterior ocelli.Occiput black covered with white hairs.
Thorax.Mesonotum dark with metallic luster and covered with erect yellow hairs.Postpronotum (humeri) and postalar calli yellowish.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellow hairs.Five longitudinal dusted bands distinct.Wings palegreyish with dark veins.Dorsal and ventral calypters pale yellow.Halteres dark yellowish.Femora dark-brown with pale apical part, mainly in the ventral area.Fore and mid tarsi and tibiae yellow; hind tibiae yellow with dark median band and with short and blunt apical processes; hind tarsi dark.Mid femur without ventral short black bristles.Hind trochanter rounded, without thorn or angular hump.Legs covered with pale hairs.
Abdomen.Dark, oval and longer than mesonotum.Tergite I completely black; tergite II with red antero-lateral spots; tergites III and IV black with pale pruinose transversal stripes interrupted in the middle; all tergites covered with short adpressed hairs of the same colour than the tegument.Sternites, anterior corner of the tergite II and the lateral margin of all tergites with long pale hairs.Sternites mainly pale, brownish posteriorly.
Male genitalia.Apical part of PL small, quadrangular in lateral view; margin of surstyle distinctly convex (Fig. 194); medial prolongation of ventral surstyle lobe well developed but not visible in lateral view (Figs 194,195).Hypandrium with thecal ridge strongly folded; apical part of S hammer-like, elongated in dorso-ventral direction (Fig. 196).

Female
Similar to the male except for the following characteristics: Ocellar triangle equilateral and covered with dark hairs.Frons black, completely covered with white pubescence except for a narrow shiny central line; yellowishwhite hairs anteriorly reclined on the lateral margins of frons.
Diagnosis.Very large species (14.0-18.6 mm) with hairy cx and reduced hairs on pa; differs from other European species by pale humeri and postalar calli; species with relatively short body hairs, short basoflagellomere, bf = 0.8-0.9(Figs 74, 77); whitish hairs on frons and face, pollinose stripes on mesoscutum, red-yellow lateral spots on tergite II and pair of pollinose stripes on tergites II-IV; antennae, tibiae and tarsi of fore and middle legs yellowish; similar in size and appearance to M. pruni Rossi, 1790 and M. clavipes but these two species do not have long hairs on the posterior side of mid coxae.Etymology.The name luteihumerus is descriptive of the pale colour of the humerus (postpronotum) in males and females.
Biology.Preferred environment: Open areas in evergreen thermophilous oak Quercus ilex and Q. suber with scattered Mediterranean brushwood on stony ground.Flowers visited: Urginea maritima.Period of flight: September.

Merodon nigritarsis Rondani, 1845
Variability.Species can vary in pollinose spots and stripes on frons, scutum and tergites.In male genitalia, size of notch on PL, shape of marginal thorn and direction of apical prominence on AL are very variable.
Remark.Merodon tricinctus Sack, 1913 is closely related and can be a synonym of M. obscuritarsis, but the relation between these two taxa will be the subject of future studies.
Range (+ data of M. tricinctus).France, Mediterranean basin and North Africa; from Spain eastwards through southern Europe to Greece, Bulgaria, Crimea, Turkey and the Caucasus; also in Israel; in Switzerland and Austria in central Europe.Diagnosis.Small (8-10 mm) species with olive-brown reflections; cx bare and pa with many hairs; scutum unpollinose; abdomen short and stocky, tergites dark, without pale spots; tergites II, III with small pollinose spots, basoflagellomere reddish; knees, tarsi, basal part and apex of tibiae pale; body hairs pale, except black hairs on vertex, apex of femora, central part of scutum and tergites II-IV; male genitalia: PL oval, with rounded top; surstyle margin slightly convex; AL small, covered with dense short hairs .

Merodon ottomanus Hurkmans, 1993
Variability.Basoflagellomere from orange to brown; black hairs on scutum and pollinose spots on male tergites may be absent.

Biology. Preferred environment: forest; open areas in
Quercus ilex / Pinus halepensis forest and lentisc scrub.Occurs at 2000 m in Turkey (Hurkmans, 1993.Period of flight: May-June. Iberian distribution.High mountains of Valencia and Alicante provinces, in the East of Spain (Fig. 255).
Range.Described from Turkey and distributed along the Mediterranean basin.Merodon parietum was described from a single male.In the Meigen collection there is one specimen with original name label and corresponding data.We accept this specimen as the holotype: male "parietum Hgg.Lusi-tania / parietum det.Loew / Lusitania coll.Winthem / Typus" (Portugal) (NHMW).
Range.Portugal, Spain, southern France (north to the Dordogne); Greece.In "Catalogue of Palaearctic hoverflies", Peck (1988) cited M. pumilus as a synonym of M. aeneus Meigen, 1822.The morphological characters (see the Key) and molecular data (Stähls, unpubl.) of these two taxa are different and we redefined M. pumilus.Identity: valid species.M. pumilus was described from a single female.In the Lucas collection there is one specimen with original name label.We accept this specimen as the holotype: female "pumilus Macq.sp.nova / Type" (Constantine, Algeria) (MNHN, Lucas collection).

Merodon pumilus Macquart in Lucas, 1849
Comment.Merodon pumilus belongs to a group of diverse and geographically usually well-separated species that occurs around the Mediterranean Basin (Vujic et al., in prep.).These taxa (aureus complex) are very closely related, and in some cases without clear morphological diagnostic features.M. pumilus is distributed in North Africa and only a few specimens of this species were found in the Iberian Peninsula.
Diagnosis.Small (8.0-13.3mm) species with hairy cx and many hairs on pa; short rounded abdomen, and thorn on hind trochanter in male (aureus group of species); abdomen and mesonotum with dense, yellow-reddish hairs in male; female abdomen with shorter, mixed pale and black hairs, tergites II-IV with clear pollinose stripes; tegument of mesonotum and tergites with golden tomentum; hind femora pale haired (with few black hairs in related M. unicolor); at least upper half of eyes black haired (pale haired in M. unicolor); basoflagellomere reddish to dark-brown, legs dark except knees, both ends of tibiae and tarsi in part, which can be paler; male genitalia (practically identical in all species from aureus group): AL undeveloped, ventral margin straight; PL with parallel margins, rounded apically, covered with long hairs; C can be slender, but without clear prominences; hypandrium narrow, elongated and sickle-shaped; S reduced .Range.Unknown.These are the first data from the Iberian Peninsula.

Male
Head.Antennae red brown; basoflagellomere pale and approximately as long as pedicel and flagellum together; apex acute.Face and frons shiny black with white hairs.Occiput shiny black covered with white pubescence and white hairs.Vertical triangle isosceles with white hairs.Ocellar triangle equilateral.Eyes with white hairs and few black hairs on the upper part.
Thorax.Mesonotum and scutellum dark green with metallic luster, with erect yellowish-white hairs, usually some short black hairs at wing basis.Posterior anepisternum, anepimeron and dorsal part of katepisternum with white hairs.Wings pale-greyish with dark veins.Dorsal and ventral calypteres pale yellow.Halteres with yellow pedicel and brown capitulum.Femora black, only pale towards apex; with long white hairs on the anterior part and short, black and adpressed posteriorly.Tibiae and tarsi yellow, the two-three apical tarsomeres dark.Tibiae and tarsi with yellow hairs and some black ones on posterior part of tibiae and dorsally on tarsi.Hind trochanter with a short thorn with two pointed teeth usually of different size.
Abdomen.Oval, slightly longer than mesonotum; dark green with metallic luster with a band (sometimes interrupted in the middle) of white pubescence on tergites II and III.Colour of abdominal hairs white except two black bands of reclined hairs on posterior third of tergite II and all of tergite III (except central dusted band).
Male genitalia.Similar to M. aureus.AL undeveloped, ventral margin straight; PL rounded on apex.Hypandrium narrow, elongated and falcate; S reduced .

Female
Similar to the male, except for the following characteristics.Frons shiny with white erected hairs, except for a line of anteriorly reclined hairs along the eyes border.Diagnosis.Small (7.3-9.3 mm) species with hairy cx and many hairs on pa, short rounded abdomen, and thorn on hind trochanter in male (aureus group of species); mesonotum pale haired, usually with few black hairs at wing basis; in male posterior 1/3 of tergite II and all of tergite III (except central pollinose stripes) black haired; female abdomen with shorter, mixed pale and black hairs, tergites II-IV with clear pollinose stripes; legs black, tibiae and tarsi yellow, the two-three apical tarsomeres dark; apical part of hind femora at least with few black hairs.M. quercetorum nov.sp. is similar to M. coerulescens Loew but can be distinguished by pale tibiae and tarsi (dark in M. coerulescens), brownish ground colour (bluish in M. coerulescens) and pale eye hairs (dark on upper third in M. coerulescens).
Iberian distribution.Cantabrian range (North of Spain) and two Natural Parks, La Font Roja and Mariola, both belonging to the Iberian mountain range (Alicante, East of Spain) (Fig. 256).
Range.Spain.Diagnosis.Big species (15-18 mm) with hairy cx and reduced hairs on pa; basoflagellomere long (bf = 2.2), four times longer than pedicel (Figs 76,79); scutum in female with two patches of black hairs anteriorly of transversal suture; tergites III, IV without or with very narrow pollinose stripes; male genitalia: anterior margin of surstyle more or less straight; PL broad, oval; inner side covered with strong setulae; AL small, rounded, covered with dense short hairs; ventral margin of hypandrium with strong setae; S elongated .
Biology.Period of flight: May.
Range.Some isolated places of the Mediterranean basin (Crete, Macedonia).These are the first data from the Iberian Peninsula.Meigen, 1822 Figs 8, 13, 24, 26, 116-121 Merodon serrulatus Wiedemann in Meigen, 1822: 360 stat. rev. Merodon lusitanicus Hurkmans, 1993: 181 syn.n.Hurkmans (1993) published Merodon serrulatus as a synonym of M. avidus in his monograph.He designated a lectotype (male) contrary to the original description that contains only one type specimen (female).The depositary Museum is also different (NHMW).We found in the col- lection of the Berlin Museum a female specimen with original name label and corresponding data, and accept this specimen as the Holotype: female "serrulatus / Portugal / Hoffmannsegg S. / 915 Type [red label]" (Portugal) (ZMHB).Based on these facts Hurkmans' designation of lectotype from non-type material is incorrect, and we reinstalled M. serrulatus as a valid species.
Variability.Antennae from black to brown; black hairs can lack on scutum, tergites and femora; knees, apex of tibiae and tarsi ventrally can be paler, pollen of scutum can be less visible; male genitalia shows variability in the shape of surstyle and size of area covered with dense short hairs on AL (Figs 118,119).Range.Portugal and Spain.These are the first data from Spain.Diagnosis.3 mm) sized, long haired species, with black body ground-colour; cx with hairs and hairs on pa reduced; scutum without clear pollinose stripes; tergites III, IV with small or absent stripe of pollen; scutum usually with stripe of black hairs between wing bases; trochanter with clear hump (Fig. 80); legs long haired; tergite II with small brownish lateral spots; male genitalia: PL rounded; marginal thorn small, invisible in lateral view; AL with long, medial prolongation; C with central apical prominence; S with large oval apical part .
Biology.Preferred environment: forest/open ground, marshy, open areas in evergreen oak maquis, garrigue, scrub-invaded grassland, and wet meadows.Flowers visited: Senecio sp.Period of flight: May, July-August.
Range.Spain.Diagnosis.Species with hairy cx and reduced hairs on pa; medium sized (13.3-14.6 mm), short haired species with reddish abdomen; hind femora with ventral bulge on basal fifth (Fig. 59); hind trochanter with clear rounded projection (Fig. 59); male genitalia: PL squarish; surstyle margin long, with strong marginal thorn; AL with short apical extension; S hammer-like .
Merodon hispanicus: Syntypes: 4 females "Andalusien, Hispania" (Spain) [these syntypes have not been traced; based on their description it is clear that they belong to Merodon unguicornis which is the only species similar to M. aureus (aeneus) with red lateral spots on tergites II and III].
Diagnosis.Small (7.3-10.0mm) species with hairy cx and many hairs on pa, short rounded abdomen, and thorn on hind trochanter in male (aureus group of species); tergite II with reddish lateral spots; tergites unpollinose; thorn on hind trochanter in male very small (Fig. 42); antennae brown; eye hairs pale-brownish, darker on upper part; mesonotum and abdomen pale haired; legs dark, knees and base of tibiae pale; male genitalia: AL undeveloped, ventral margin straight; PL with parallel margins, rounded on apex, covered with long hairs; hypandrium narrow, elongated and sickle-shape; S reduced .
Variability.Usually tergite III also with reddish lateral spots, but they can be small or absent in some specimens.
Additional published records.Arias (1912); Andreu (1926);Gil-Collado (1930); Peck (1988)  Merodon unicolor was described as a variety of M. aeneus Meigen, 1822 from a single male.In the Strobl collection there is one specimen with original name label and corresponding data.We accept this specimen as the holotype: male "v.unicolor m / Spain./ Typus" (Spain: Escorial) (NMBA).Peck (1988) cited M. unicolor as a synonym of M. aeneus.The morphological characters (see the Key) and molecular data (Ståhls, unpubl.) of these two taxa are different and we redefined M. unicolor.Identity: Valid species.
Diagnosis.Small (7.3-11.0mm) species with hairy cx and many hairs on pa, short rounded abdomen, and thorn on hind trochanter in male (aureus group of species); abdomen and mesonotum with dense, yellow-reddish hairs in male; female abdomen with shorter, mixed pale and black hairs, tergites II-IV with clear pollinose stripes; tegument of mesonotum and tergites with golden tomentum; hind femora with few black hairs on apical part (pale haired in related M. aureus); at eyes pale haired rarely with few black hairs on upper corner (at least upper half with black hairs in M. aureus); basoflagellomere reddish to dark-brown, legs dark except knees, both ends of tibiae and tarsi in part, that can be paler; male genitalia: AL undeveloped, ventral margin straight; PL with parallel margins, rounded at apex, covered with long hairs; C can be slender, but without clear prominences; hypandrium narrow, elongated and sickle-shaped; S reduced .
Biology.Preferred environment: Open ground and wet meadows in mountainous areas (up to 2250 m).Flowers visited: Anthemis mixta.Period of flight: April-August.
Range.Spain and Northwest Afria.Western Mediterranean species.
Merodon aeneus Meigen, 1822: 367.In the Biosystematic Database of World Diptera, Thompson (2004) cited Merodon aureus as a senior synonym of M. aeneus.The type of M. aeneus (Mühlfeld in Austria) has not been located.Based on the original descriptions of both names, and after examination of Museum material (which fits descriptions) from Germany and Austria, which all belongs to one species, we decided to follow this synonymy.

DISCUSSION
The Mediterranean basin is considered one of the "hotspots" of biodiversity of the planet (Myers et al., 2000); moreover, species endemism is very high in this region.Climatic variation during the Pleistocene had a decisive influence in shaping the composition and distribution of mediterranean species and communities (Blondel & Aronson, 1999).
The Old world genus Merodon Meigen, 1803 (Syrphidae, Diptera) is one of the most widespread in the Mediterranean region (Speight, 2006).In a previous catalogue for the Iberian Peninsule (Marcos-García et al., 2002), 30 Merodon species were compiled from the bibliography.In the present study, nine of them have been synonymized, eight new species have been described and six species are cited for the first time for the Iberian fauna.The updated number of the Merodon species registered in the Iberian Peninsula is thus 34.In France, a neighbouring country to the Iberian Peninsula and with a slightly bigger geographical extention, 32 species have been registered (Dussaix, 2004), 50% of them shared with the Iberian Peninsula.
A 36.4% of the Iberian Merodon species are also present in the North of Africa and two of them (M.elegans and M. pumilus) are endemic to the Iberian Mediterranean region and Northwest of Africa.This similarity could be explained because the "Ibero-Mauritanian" plate has been a fertile matrix for differentiation in many groups of plants and animals and in this case it seems probable that these species colonized Iberia during the Messinian Salinity Crisis that established a land bridge between the present day Morocco and the Iberian Peninsula 5.6 My ago (Blondel & Aronson, 1999).
It should be noted that the high number of Iberian endemic species of the genus Merodon (14 = 41.2%),one of the highest through the entire range of this genus, could be related to one distinctive trait of the Mediterranean flora, in addition to sclerophyly and evergreenness, the bulbous life form.These geophytes have a fleshy subterranean storage organ which is usually the only portion of the plant that survives the extended period of summer dormancy.In fact, the Iberian Peninsula is the centre of diversity for some subgenera of Narcissus Spach (Rivera et al., 2003), one of the main groups of feeding plants for the larvae of Merodon species (Rotheray, 1994).Only Turkey surpasses the high number of species and endemicity in the Mediterranean basin with 60 registered Merodon species (Siribiyic, pers.com.), of which only 13 live in the Iberian Peninsula.Turkey is another center of diversity of this genus in the Mediterranean basin.
Although Merodon species are adapted to the xerothermic Mediterranean environment, 50% of the Iberian species are also distributed along the Eurosiberian region of the Iberian Peninsula, with M. crypticus being exclusive to this biogeographical area.
On average, levels of endemism increase as altitude increases.In the Mediterranean mountain ranges, whether continental or insular, the percentage of endemic species is very high, albeit quite variable (Blondel & Aronson, 1999).In the Iberian Peninsula, this fact has been also shown by Gómez-Campo & Herranz-Sanz (1993) in plant taxa (31% are restricted to the mountains and levels of endemism can reach upto 50%).Concerning to the Merodon species, each Iberian mountain chain comprises some endemic species and more than 60% of the Iberian species are present in the mountains of the Sistema Central of Spain where the percentage of endemism is the highest (46.2%).
The adult flight activity of Merodon species throughout the year can be summarised in three phenologic models: early Spring species (45.5%), early Autumn species (15.2%) and species with a longer flight period, from spring to autumn (39.4%).
It should be noted that all the Iberian and Western Mediterranean endemic species have fortunately at least part of their distribution area inside areas with some degree of protection as National or Natural Parks.

Figs
Figs 67, 72, 104, 107, 161MaleHead.Antennae dark brown; basoflagellomere 1.5 times as long as wide; dorsal margin plain, apex acute; basoflagellomere and pedicel with some red ventral colouration.Face and frons shiny black covered with dense white pubescence and yellowish-white hairs.Oral margin bare and black lustrous.Vertical triangle isosceles, twice as long as eye contiguity distance, shiny black with white pubescence and red hairs.Ocellar triangle isosceles.Eyes with white hairs.Thorax.Mesonotum and scutellum dark-green with metallic luster and covered with erect red hairs; five longitudinal lines of pubescence only visible under microscope.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellow long hairs.Wings palegreyish with dark veins.Dorsal and ventral calypters pale-yellow.Halteres yellow.Femora dark-brown with pale apical part.Fore and mid tibiae yellow in basal part

Figs
Figs 62, 69, 73, 106, 162    MaleHead.Antennae dark brown; basoflagellomere 1.2 times as long as wide, upper margin slightly concave, apex acute.Face, frons and occiput black covered by dense white pubescence and long white hairs.Oral margin bare and lustrous black.Ocellar and vertical triangles isosceles.Eyes with white hairs; vertical triangle with white and black erect hairs.Thorax.Mesonotum and scutellum dark green with metallic luster and covered with erect pale-yellow hairs and one transverse band of black hairs at the level of wing insertion.Posterior anepisternum, anepimeron and dorsal part of katepisternum with yellowish-white hairs.Wings pale-greyish with dark veins.Dorsal and ventral calypters pale yellow.Halteres with yellow capitulum and pedicel.Femora dark brown with pale apical part.Fore and mid tibiae yellow in basal part, with distal dark top; hind tibiae yellow with dark median band and with a sharp apico-medial process.Tarsi dark, with black bristles and some black tarsomeres, partly pale.Hind trochanter with a distinct rounded thorn covered with long, dense hairs.Legs with pale hairs except some black reclined Figs 165-169.Merodon flavus, male genitalia.165 -epandrium, lateral view; 166 -left surstyle, anterior view; 167 -surstyle margin; 168 -hypandrium, lateral view; 169 -apical part of hypandrium, anterior view.Scale 0.2 mm.

Biology.
Preferred environment: scrub/open ground.This species has been found on low-lying, sandy, herbrich grassland containing abundant wild onion flowers (Allium sp.), scattered clumps of sedge and occasional stems of Arundo, at the edge of Mediterranean salt-marsh, where the fluctuating ground-water levels would, during the winter, bring the water level very close to the ground surface.It has also been found in open dry Pinus forest (P.halepensis) on largely bare, stoney ground and in open areas within Quercus ilex forest, garrigue and matorral.Flowers visited: Calystegia sp. and Cistus sp.Period of flight: April-September.Iberian distribution.Widespread in the Iberian Peninsula: Cantabrian mountains (North of Spain), Iberian mountain range (East of Spain), and Sistema Central (Fig. 248).

Biology.
Preferred environment: Forest/open ground; open areas in Quercus ilex forest and tall-herb ruderal communities on sparsely-vegetated open ground, close to seasonal rivers and streams or drainage ditches.Flowers visited: tall yellow Composites; Adonis sp., Anacyclus sp., and Ranunculus sp.Period of flight: May-June and August-September.

Biology.
Preferred environment: forest/open ground; unimproved montane grassland in southern Europe and open areas in mesophilous Fagus and Quercus ilex forests.Period of flight: March-April (Malta) and July to September, with a peak at end August-beginning September.

Biology.
Preferred environment: High mountain grassland in the North of Spain and open areas with Mediterranean scrub in high mountains in the East of Spain.Flowers visited: Merendera montana.Period of flight: September.Iberian distribution.Cantabrian range (North of Spain) and Iberian mountains (East of Spain) (Fig. 252).Range.Spain.
Iberian distribution.Sistema Central and Bético in the southern half of Spain (Fig.257).
Biology.Preferred environment for A and B: Forest/open ground; humid Fagus/Picea forest, thermophilous Quercus forest.Evergreen Quercus forest (Q.ilex); dry, pasture, old almond, cherry and olive orchards.Flowers visited: Apiaceae, Achillea sp., Euphorbia sp., and Muscari sp.Period of flight: June-July in northern parts, but also a second generation, August-September, further south.From Southern Scandinavia to the Mediterranean and North Africa; from Spain through most of central and southern Europe to Turkey and European parts of Russia. Range.