Megaselia Rondani, 1856

Disney, R. H. L., Prescher, S. & Ashmole, N. P., 2010, Scuttle flies (Diptera: Phoridae) of the Canary Islands, Journal of Natural History 44 (3 - 4), pp. 107-218 : 121-130

Genus Megaselia Rondani

This huge genus includes more than half the species in the family. Updates to the identification literature, since the review of Disney (1994b), for the western Palaearctic species are covered by Naumov (1992), Buck and Disney (2001), Disney (1999, 2000, 2001b, 2002a, c, 2004, 2006a, b, c, 2009), Disney et al. (2000, 2001), Mostovski and Disney (2002), Brenner (2004) and Polidori et al. (2005). The existing keys (e.g. Disney 1989a and the keys cited therein) only allow for the identification of males in most cases.

The frontal bristles are labelled in Figures 12A,B and 43B and the wing veins in Figures 56A and 64A , the latter labels the costal cilia and axillary bristles as well. Other critical features include some internal features such as the presence (e.g. Figure 15D ) or absence of subcutaneous pit sensilla (SPS vesicles) in the postpedicels (third antennal segments) of both sexes; and in females the form of Dufour’s crop mechanism (situated in the base of the abdomen or in the thorax) (e.g. Figures 18C and 45B ), the furca (the internalized sternite 9) and other vaginal sclerites (e.g. Figures 28C , 40A , 45C and 53B ), when these are sclerotized. The male hypopygium has been critical in the recognition of species. It comprises a dorsal shield (the epandrium) and a ventral shield (the hypandrium) which embrace the base of the dorsal anal tube and the ventral penis complex. The latter may look very different when withdrawn compared with when it is extruded (see Figures 17A,B , 48B and 49A ).

Key to species of Megaselia males

1. Mesopleuron with hairs and sometimes with bristles as well............ 2 Mesopleuron bare.............................................16

[Note. One species keys both ways as it has nought to a few hairs.]

2. A double row of four to six spines beneath the base of hind femur ( Figure 59 ). Hypandrial lobe of left side large and bare ( Figure 60 )................................................... Megaselia basispinata (Lundbeck) Without this combination....................................... 3

3. Posterodorsal region of epandrium inflated (Figure 81). Hind femur as Figure 82................................ Megaselia coccyx Schmitz Not so....................................................... 4

4. Haltere knob yellow, contrasting with brown stem................... 5 Haltere knob brown............................................ 9

5. Mesopleuron with uniform small hairs only. (Palps brown. With seven or eight short bristle-like hairs below base of hind femur. Mid femur dark brown like hind femur. Last tarsal segment of front leg a little broader than fourth segment. Hypopygium otherwise)...... Megaselia nigrifemorata (Santos Abreu) With some clearly differentiated bristles at rear of patch of hairs on mesopleuron................................................. 7

6. Palps yellow.................................................. 7 Palps brown.................................................. 8

7. Hairs below base of hind femur only a little differentiated from adjacent hairs of anterior face. Hypopygium as Figures 122 and 123.................................................... Megaselia pleuralis (Wood) Hairs below base of hind femur clearly differentiated (Figure 157). Hypopygium as Figure 156. (Wing membrane grey, being evident to naked eye when viewed against a white background)....... Megaselia stichata (Lundbeck)

8. Haltere knob dusky yellow (palps only lightly tinged brown).......... Return to couplet............................................. 7 Haltere clearly brown or greyish brown............................ 9

9. Hairs at rear of T6 scarcely differentiated from those on rest of tergite. Right side of epandrium extended ventrally ( Figures 21A and 69B )...........10 Hairs at rear of T6 clearly longer than rest of hairs on tergite. Epandrium not thus......................................................11

10. Hairs of lower face of venter greatly reduced on segments 3 and 4, so that these segments appear to be bare at lower magnifications. Hypopygium as Figure 21A,B ................................ Megaselia ashmolei Disney Hairs below segments 3–4 only slightly smaller than those on segment 5. Hypopygium as Figure 69A,B ................ Megaselia verralli (Wood)

11. Epandrium with subequal posterolateral lobes bearing long bristly hairs that extend forwards in a band adjacent to lateral margins ( Figures 30 and 31 )...................................................... 12 Not so...................................................... 13

12. A small, pale yellowish grey, left hypandrial lobe present ( Figure 30B )....................... Megaselia chinyeroensis Disney sp. nov. Hypandrial lobes absent ( Figure 31 ).......... Megaselia cirratula Schmitz

13. Basitarsus of front leg a little swollen and with some rows of hairs of ventral face reduced to minute spinules ( Figure 41C ). Hypopygium as Figure 41B . Megaselia manicata (Wood) Front basitarsus not thus. Hypopygium otherwise................... 14

14. Hairs below basal half of hind femur densely crowded towards base ( Figure 36A ). Hypopygium as Figure 36B ................ Megaselia hirticrus (Schmitz) Hairs below basal half of hind femur not crowded in this way. Hypopygium otherwise.................................................... 15

15. Wing membrane distinctly tinged yellowish grey............................................................. Megaselia umbrata Schmitz Wing membrane almost colourless............. Megaselia patula Schmitz

16. A short row of four or five spine-like bristles, with bent over tips, clearly differentiated from hairs beneath base of hind femur ( Figure 40B ). Hypopygium as Figure 40D ............. Megaselia longiseta (Wood) Without such row of differentiated spines. Hypopygium otherwise..... 17

17. Hairs at tip of anal tube strongly differentiated as feathered bristles ( Figure 60A )............................. Megaselia scalaris (Loew) Not so...................................................... 18

18. Abdominal tergites ( Figure 54A ) and epandrium ( Figure 54B ) with strong feathered bristles................. Megaselia rufipes (Meigen) Without this combination.................................. 19

19. Hind tibia with some differentiated anterodorsals in basal half at least as well as the longer, more spine-like, posterodorsal hairs. Scutellum with four strong bristles........................................ 20 Not with this combination.................................. 22

20. Spines of apical comb of hind tibia all simple.................. 21 Apical comb of hind tibia with two to five bifurcated spinules ( Figure 12C ). (Hypopygium as Figure 13 , the cerci lacking spines)........................................ Megaselia aequilateralis Schmitz

21. Hypopygium as Figure 42A , each cercus having a strong down-curved spine............................... Megaselia meigeni (Becker) Hypopygium as Figure 50B , the hairs of the cerci being all simple................................ Megaselia plurispinulosa (Zetterstedt)

22. Apical third of hind tibia modified as Figure 44A . Hypopygium as Figure 44B , the median hypandrial process having a hooked tip........................................................ Megaselia nigra (Meigen) Tip of hind tibia not so modified. Hypopygium otherwise.............23

23. Vein Sc strong and its tip fused to vein 1 (R1) ( Figure 56A )......... 24 Sc fades away before reaching vein 1 and often weakly developed or obscure................................................. 26

24. Scutellum with four bristles. Towards sides of T2 with a row bristles running parallel to edge. Hypopygium as Figure 51 ............................................................... Megaselia ruficornis (Meigen) Anterior scutellars are fine hairs at most as long as those at rear of scutum between dorsocentral bristles. Few, if any, bristle-like hairs towards edge of T2 and when present not forming a continuous row. Hypopygium otherwise................................................ 25

25. Hairs of epandrium relatively short and fine ( Figure 16C ). (No hairs on inner posterior face of front coxa. Haltere knob varies from pale yellow to yellowish brown or darker).................. Megaselia angusta (Wood) These hairs longer and more robust ( Figure 26A ). (Haltere knob brown. Notopleuron with two strong bristles only)........................................................ Megaselia bistruncata Schmitz

[Note. If costa is well under half length of wing proceed to couplet 26.]

26. Notopleuron with three strong bristles. Haltere knob yellow or brown...27 Notopleuron with only two strong bristles. Haltere knob yellow..... 37

27. Haltere knob brown............................................28 Haltere knob essentially yellow, even if sometimes a little dusky..... 34

[Note. Borderline species are keyed both ways.]

28. A palisade of long hairs along ventral edge of left side of epandrium ( Figures 30B , 31 )......................................Return to couplet 11 Without such a palisade (e.g. Figures 20B and 43C )............... 29

29. Labella of proboscis relatively large and with dense fields of small pale spinules on their lower faces. The dorsal face of epandrium shortened but anal tube relatively long ( Figure 43C )....... Megaselia minor (Zetterstedt) Without this combination................................... 30

30. Sides of epandrium with robust, feathered, bristles (and left lobe of hypandrium tapered and largely bare) ( Figures 20B and 68A,B )..............31 Hairs of epandrium fine and not feathered (e.g. Figure 38C )........ 33 31. Abdominal venter straw yellow.................................. 32 Venter brown. (Wing> 1.4 mm long and the costal cilia (on section 3) at least 0.1 mm long. Postpedicels dark brown and large, with diameter> 0.15 mm. Hypopygium as Figure 20B ).... Megaselia apozona Schmitz

32. Hind femora essentially brown. Venter with numerous conspicuous hairs ( Figure 35C )............................. Megaselia halterata (Wood) Hind femora straw yellow. (Wing <1.6 mm long and the costal cilia at most 0.1 mm long. Postpedicels light brown and their diameter <0.15 mm. Hypopygium as Figures 68A,B )....................................................... Megaselia subfuscipes Schmitz

33. Labella of proboscis with dense fields of pale spinules on lower faces. Dorsal face of epandrium shortened and anal tube relatively long ( Figure 38C ).............................................. Megaselia lata (Wood) With only a few scattered small spinules on labella. Hypopygium otherwise............................................... 34

34. Epandrium with robust feathered bristles, left lobe of hypandrium a small tapered spike, venter straw yellow and with numerous conspicuous hairs ( Figure 35C ).................................. Return to couplet 31 Without this combination.................................. 35

35. At least the middle and hind femora mainly brown.................. 36 All femora yellow. (Hypopygium as Figure 15C , the epandrium being typically extensively a pale straw yellow)..... Megaselia albicaudata (Wood)

36. Hypopygiyum as Figure 11B . Haltere knob whitish yellow. (Postpedicels with many SPS vesicles)...................... Megaselia abdita Schmitz Hypopygium as Figure 67A,B . Haltere brown. (Wing membrane almost colourless. Hind femur not so narrow. Postpedicels vary from light to dark brown, <0.15 mm in diameter and with at least three dozen pale SPS vesicles some of which are as large as sockets of lower SA bristles).................................... Megaselia striolata Schmitz

[Note. the hitherto unknown male of species Y will probably run out here. Its legs are much paler than those of M. abdita and its wing membrane much more tinged grey than that of M. striolata .]

37. Labella of proboscis with dense fields of small colourless spinules on lower faces....................................................... 38 With only a few scattered spinules on lower faces of labella........ 39

38. Hypopygium as Figure 24A . (Wing as Figure 25D . Hind femur as Figure 24B ).................................. Megaselia berndseni (Schmitz) Hypopygium as Figure 39B ............... Megaselia latior Schmitz

39. Notopleuron with a cleft in front of anterior bristle ( Figure 27A )....... 40 No such cleft............................................ 42

40. All femora dark brown. Hypopygium as Figure 27B ..................................................... Megaselia brevicostalis (Wood) At least front femur is more yellowish brown. Hypopygium otherwise...... 41

41. Epandrium with shortened dorsal face and with numerous long hairs ( Figure 37B )........................... Megaselia intermedia (Santos Abreu) Epandrium not shortened dorsally and with a single long, bristle-like, hair each side, the rest being shorter and finer ( Figure 33A )............................................... Megaselia giraudii (Egger)

42. Veins 4 and 5 (the first two thin veins) subparallel in middle third ( Figure 64A ). Hypopygium as Figure 63B ........... Megaselia stenoterga Disney Veins 4 and 5 divergent throughout (e.g. Figure 25D ). Hypopygium otherwise................................................ 43

43. Left lobe of hypandrium almost vestigial and hairs at tip of proctiger clearly longer and more robust than those on cerci ( Figure 46A )................................................... Megaselia oxybelorum Schmitz Without this combination................................... 44

44. Hairs at tip of proctiger longer and more robust than hairs on epandrium and left lobe of hypandrium relatively large (and with fine hairs on entire lower face) ( Figure 29A ). (Hairs at rear of T6 not obviously differentiated from those on rest of tergite, the dorsal face of epandrium usually lacking hairs)...................... Megaselia brevissima (Schmitz) Hairs at tip of proctiger at most as strong as longest hairs on epandrium and left lobe of hypandrium relatively short ( Figure 19A )............................................. Megaselia angustiata Schmitz

Key to species of Megaselia females

1. Veins 4 and 5 converge and then diverge ( Figure 64B ). T3 and T4 conspicuously narrowed ( Figure 63C )............... Megaselia stenoterga Disney Not so................................................... 2

2. Mesopleuron with hairs and sometimes with bristles as well............ 3 Mesopleuron bare......................................... 15

[Note. One species keys both ways as it has nought to a few hairs.]

3. Haltere knob yellow............................................ 4 Haltere knob brown........................................ 9

4. Mesopleuron with one or more bristles at rear of hair patch............ 5 Mesopleuron with hairs only.................................. 7

5. Labrum relatively broad, its greatest breadth being as broad as or greater than that of a postpedicel ( Figures 49B , 66B )........................ 6 Labrum relatively narrow ( Figure 23B ) its greatest breadth distinctly less than that of a postpedicel. (Epiproct with distinct posterolateral ‘corners’ as Figure 23A )................... Megaselia basispinata (Lundbeck)

6. T7 more-or-less rectangular (e.g. Figure 48A ). Posterolateral lobes of sternum 8 distinct. (Mid tarsi typically with posterodorsal hair palisades on all five segments............................ Megaselia pleuralis (Wood) T7 strongly tapered ( Figure 66C ). Posterolateral lobes of sternum 8 weak ( Figure 66A )...................... Megaselia stichata (Lundbeck)

7. Palps straw yellow............................................. 8 Palps brown........ Megaselia nigrifemorata (Santos Abreu) (see text)

8. With one or two hairs at base of vein 3. Each labellum with at least 30 small spinules on lower face. (All five segments of front and mid tarsi with a posterodorsal hair palisade).................... Megaselia coccyx Schmitz No hair at base of vein 3. Each labellum with fewer than 20 small spinules on lower face..................................... 15

9. Palps brown................................................. 10 Palps straw yellow........................................ 12

10. All femora dark brown........................................ 11 Front femur yellowish brown............. Megaselia umbrata Schmitz

11. Mesopleuron with a differentiated bristle at rear of hair patch. (T6–T7 as Figure 41A )............................ Megaselia manicata (Wood) Mesopleuron with hairs only.............. Megaselia patula Schmitz

12. Hairs below basal half of hind femur scarcely differentiated from adjacent hairs of anterior face. Each labellum with more than 40 small spinules on lower face. Lower SAs clearly weaker than upper pair........................................................ Megaselia hirticrus (Schmitz) Hairs below basal half of hind femur clearly longer and more robust than adjacent hairs of anterior face. Each labellum with fewer than 20 small spinules on lower face. Lower SAs robust and almost as long as upper pair.................................................... 13

13. Wing membrane lightly tinged grey............................... 14 Wing membrane colourless...... Megaselia ashmole Disney ) (see text)

14. Palps pale straw yellow. At least front femora mainly yellow to yellowish brown.......... Megaselia cirratula Schmitz and Megaselia chinyeroensis Disney sp. nov. [the female of the latter being unknown] Palps yellow tinged light brown. All femora brown............................................................ Megaselia verralli (Wood)

15. Abdominal tergite 6 longer than broad and tapered Figures 42B , 50A ). Hind tibia with some differentiated anterodorsals in basal half but these are weaker than the posterodorsals and are rarely reduced in number or absent. Front tibia with a dorsal row of small spines differentiated from adjacent hairs. Scutellum with four bristles................................ 16 Without this combination.................................. 18

16. Apical comb of hind tibia with two to five bifurcated spinules ( Figure 12C ). (Postpedicels essentially yellow. ALs higher on frons than upper SAs)...................................... Megaselia aequilateralis Schmitz Spinules of apical comb of hind tibia all simple.................. 17

17. Postpedicels larger (about 0.2 mm wide). Wing typically> 3 mm long, but the one to three hairs at base of vein 3 are very fine (at most 0.04 mm long) and clearly not as robust as costal cilia in vicinity of humeral cross vein. T5–T6 as Figure 42B ............................ Megaselia meigeni (Becker)

Postpedicels smaller (about 0.15 mm wide). Wing typically smaller (<3 mm long) and the one to three hairs at base of vein 3 about as robust as costal cilia in vicinity of humeral cross vein and typically> 0.05 mm long. T5–T6 as Figure 50A ...... Megaselia plurispinulosa (Zetterstedt)

[Note. Both species are variable and are more confidently distinguished in the male sex.]

18. T2–T4 markedly shortened ( Figure 26B ).... Megaselia bistruncata Schmitz Not so.................................................. 19

19. T3 and T4 narrower than T5 (Figure 47A)........................................................ Megaselia oxybelorum Schmitz These tergites broader than T5............................... 20

20. With four bristles on the scutellum................................21 Anterior scutellars reduced to fine hairs (subequal to those at rear of scutum between the dorsocentral bristles)......................... 24

21. Abdominal tergites partly yellow and T6 short but clearly broader than T5 ( Figure 60B ).............................. Megaselia scalaris (Loew) Abdominal tergites entirely brown and T6 longer and clearly narrower than T5................................................. 22

22. Sternum of eighth abdominal segment with a pair of hairy lobes ( Figures 34A and 53A ).................................................23 S8 with a single large, long-haired, lobe ( Figure 37A )........................................... Megaselia intermedia (Santos Abreu)

23. Anterior margin of T4 narrower than its posterior margin ( Figure 53A ). Venter with strongly differentiated bristle-like hairs at rear of segments 3–6 and even longer bristles at sides of T2. S8 lobes as Figure 50A ................................................ Megaselia ruficornis (Meigen) Anterior margin of T4 broader than posterior margin. Venter and T2 bristly hairs weaker and less numerous. S8 lobes as Figure 34A ............................................ Megaselia giraudii (Egger)

24. Vein Sc strong and its tip fusing with vein 1.........................25 Sc fading away before reaching vein 1 or generally obscure......... 26

25. Lower SAs clearly shorter and less robust than upper pair and weaker than apical bristles of palps. Propleuron with hairs close to hind margin (mainly in an upper and a lower cluster). (No hairs on inner posterior face of front coxa. Haltere knob varies from pale yellow to yellowish brown or darker. DCM bilobed behind, Figure 18C )............ Megaselia angusta (Wood) Lower SAs almost as long and robust as upper pair and subequal to those at tip of palps. Propleuron with several hairs in middle (in front of anterior spiracle) in addition to the upper and lower clusters near hind margin. (T6–T10 as Figure 55 . Dufour’s crop mechanism bilobed behind)...................................... Megaselia rufipes (Meigen)

26. Notopleuron with only two bristles. Haltere knob yellow..............27 Notopleuron with three bristles. Haltere knob yellow or brown...... 31 27. Abdominal sternum 8 with a pair of posterolateral short lobes......... 28 S8 with a single, long-haired, median lobe at rear margin ( Figure 39A )...................................... Megaselia latior Schmitz

28. T6 and T7 as Figure 25A . (S8 lobes small but extended by a bare, greyish, posteriorly rounded lobe)................. Megaselia berndseni (Schmitz) T6 and T7 otherwise ( Figures 19C , 28A and 29C )................ 29

29. With numerous (> 60) hairs on segments 2–6 of abdominal venter. T6 as Figure 28A . Furca complex as Figure 28c ............ Megaselia brevicostalis (Wood) With only a few hairs (<20) on segments 4–6 (mainly on 6) of venter. T6 and furca complex otherwise and usually only weakly sclerotized or unsclerotized............................................ 30

30. T5 with a shallow, but distinct, median emargination of its hind margin ( Figure 19C )........................... Megaselia angustiata Schmitz T 5 with an almost straight hind margin ( Figure 29C ). (Outermost axillary bristle longer than costal cilia).......... Megaselia brevissima Schmitz

31. Haltere knob brown........................................... 32 Haltere knob yellow....................................... 36

[Note. Some variable species are keyed both ways.]

32. Greatest breadth of T6, which tapers, subequal to or less than length ( Figures 20A , 68C ). SPS vesicles pale, subdivided by radial lines....... 33 T6 plainly broader than long ( Figures 40B , 67C ). SPS vesicles darker and lacking radial lines or else absent............................. 34

33. Costal cilia (on section 3) at least 0.12 mm long. Postpedicels dark brown. T5–T7 as Figure 20A, T 5 being> 0.4 mm wide.............................................................. Megaselia apozona Schmitz Costal cilia at most 0.11 mm long. Postpedicels light brown. T5–T7 as Figure 68C, T 5 being <0.4 mm wide.... Megaselia subfuscipes Schmitz

34. Abdominal venter with <60 hairs on segments 3–6.................. 35 Venter with at least 60 hairs on segments 3–6. (T6–T7 as Figure 67C . Wings only lightly tinged grey and thin veins yellowish grey. Palps vary from pale straw yellow to brown. Postpedicels with many SPS vesicles)........................................ Megaselia striolata Schmitz

35. T7 longer than greatest breadth. With a small, sometimes minute, hair at base of vein 3................................................ 36 T7 broader than long ( Figure 40C ). No hair at base of vein 3. (Wings dusky with large anal angle and dark grey thin veins. Palps brownish yellow. No SPS vesicles in postpedicels)...... Megaselia longiseta (Wood)

36. Anterolateral bristles little, if any, higher on frons than upper SAs. Abdominal tergite 6 broader than long or length and breadth subequal........ 37 AL bristles clearly higher on frons than upper SAs ( Figure 43B ). T6 at least as long as broad ( Figure 43A )...... Megaselia minor (Zetterstedt)

37. Venter with numerous (> 100) hairs on segments 3–6.................38 Venter with relatively few (<70) hairs on these segments........... 39

38. T5–T6 as Figure 11A . All femora brown. (Wing membrane almost colourless. Haltere knob pale yellow)................ Megaselia abdita Schmitz T 6–T7 as Figure 35A . Front and mid and femora straw yellow........................................... Megaselia halterata (Wood)

39. With conspicuous SPS vesicles in postpedicel ( Figure 15D ). (All femora straw yellow apart from tip of hind femur. T6 as Figure 15B . DCM as Figure 15A )................................. Megaselia albicaudata (Wood) SPS vesicles absent or obscure............................... 40

40. Well sclerotized furca as Figure 45C . Lower SAs shorter than upper postorbital bristles. Costal cilia (of section 3) at least 0.11 mm long. (T5–T7 as Figure 45A )............................... Megaselia nigra (Meigen) Furca not sclerotized. Lower SAs longer than upper postorbital bristles. Cost cilia <0.10 mm long................................... 41

41. Labrum pale straw yellow. T5–T7 as Figure 70 . Sternite 7 absent...................................................... Megaselia species Y Labrum brown. T5–T7 as Figure 38A . Sternite 7 as Figure 38B ............................................... Megaselia lata (Wood)

Figures

Figure 5. Conicera tibialis. (A) Female, anterior face of hind tibia (hairs omitted). (B) Male, posterior face of mid femur.(C) Female, postpedicel. (D) Male, postpedicel.Scale bars: 0.1 mm.

Figure 11. Megaselia abdita. (A) Female abdominal tergites 5–6. (B) Male, left face of hypopygium. Scale bars: 0.1 mm.

Figure 12. Megaselia aequilateralis. (A) Male, frons (with bristles represented by their sockets only) (ML, mediolateral bristle; PO, pre-ocellar bristle; AL, anterolateral bristle; A, antial bristle). (B) Female, frons (US, upper supra-antennal bristle, LS, lower SA bristle). (C) Female, posterior face of tip of hind tibia. Scale bars: 0.1 mm.

Figure 13. Megaselia aequilateralis male, left face of hypopygium. Scale bar: 0.1 mm.

Figure 15. Megaselia albicaudata. (A) Female, Dufour’s crop mechanism. (B) Female, abdominal tergite 6. (C) Male, left face of hypopygium. (D) Male, outline of postpedical with internal SPS vesicles. Scale bars: 0.1 mm.

Figure 16. Megaselia angusta male. (A) Frons, with bristles represented by their sockets only. (B) Right wing. (C) Left face of hypopygium. Scale bars: 0.1 mm.

Figure 17. Megaselia angusta male, left lobe of hypandrium and penis complex extruded (A) and withdrawn (B) (a, apical sclerite; f, pre-apical fan). Scale bar: 0.1 mm.

Figure 18. Megaselia angusta. (A–E) Female, abdominal features. (A) Sternite 6. (B) Tergite 7. (C) Dufour’s crop mechanism. (D) Sternite 7. (E) Rear margin of sternum 8. (F) Male, posterior face of hind femur. Scale bars: 0.1 mm.

Figure 19. Megaselia angustiata. (A) Left face of male hypopygium. (B) Dufour’s crop mechanism of female. (C) Female abdominal tergites 3–6. Scale bars: 0.1 mm.

Figure 20. Megaselia apozona. (A) Female abdominal tergites 5–7. (B) Left face of male hypopygium. Scale bars: 0.1 mm.

Figure 21. Megaselia ashmolei male. (A) Right face of posteroventral lobe of epandrium. (B) Left face of hypopygium. Scale bar: 0.1 mm.

Figure 23. Megaselia basispinata female. (A) Abdominal tergites from T6 onwards. (B) Distiproboscis from above. Scale bars: 0.1 mm.

Figure 24. Megaselia berndseni male. (A) Left face of hypopygium. (B) Posterior face of hind femur. Scale bars: 0.1 mm.

Figure 25. Megaselia berndseni. (A) Female abdominal tergites 6–7. (B) Female sternite 7. (C) Female, Dufour’s crop mechanism. (D) Male, right wing. Scale bars: 0.1 mm.

Figure 26. Megaselia bistruncata. (A) Male, left face of hypopygium. (B) Female, abdominal tergites 2–6. Scale bars: 0.1 mm.

Figure 27. Megaselia brevicostalis male. (A) Left notopleuron (h, humeral bristle; c, notopleural cleft; m, upper edge of mesopleuron; n, notopleural bristles). (B) Left face of hypopygium. Scale bars: 0.1 mm.

Figure 28. Megaselia brevicostalis female, details of abdomen. (A) Tergites 5–7. (B) Sternite 7. (C) Furca (f) and vaginal sclerites (v). Scale bars: 0.1 mm.

Figure 29. Megaselia brevissima. (A) Left face of male hypopygium. (B) Dufour’s crop mechanism of female. (C) Female abdominal tergites 3–6. Scale bars: 0.1 mm.

Figure 30. Megaselia chinyeroensis male hypopygium. (A) Right face. (B) Left face. Scale bar: 0.1 mm.

Figure 31. Megaselia cirratula male, left lateroventral view of hypopygium. Scale bar: 0.1 mm.

Figure 33. Megaselia giraudii male. (A) Left face of hypopygium. (B) Left face of notopleuron (S, anterior spiracle; N, notopleural bristles; nc, notopleural cleft; M, upper edge of mesopleuron; T, tegula). Scale bar: 0.1 mm.

Figure 34. Megaselia giraudii female. (A) Lobes at rear of abdominal sternum 8. (B) Dufour’s crop mechanism. Scale bar: 0.1 mm.

Figure 35. Megaselia halterata. (A) Female abdominal tergites 5–7. (B) Egg, with anterior end facing top of page. (C) Left face of male hypopygium. Scale bars: 0.1 mm.

Figure 36. Megaselia hirticrus male. (A) Posterior face of base of hind femur. (B) Left face of hypopygium. Scale bars: 0.1 mm.

Figure 37. Megaselia intermedia. (A) Female, median lobe at rear of abdominal sternum 8. (B) Male, left face of male hypopygium. Scale bar: 0.1 mm.

Figure 38. Megaselia lata. (A) Female, abdominal tergites 5–7. (B) Female, sternite 7. (C) Male, left face of hypopygium. Scale bars: 0.1 mm.

Figure 39. Megaselia latior. (A) Female, median lobe at rear of abdominal sternum 8. (B) Male, left face of male hypopygium. Scale bars: 0.1 mm.

Figure 40. Megaselia longiseta. (A) Female, furca (anterior end towards top of page). (B) Male, posterior face of base of hind femur. (C) Female, abdominal tergites 5–7. (D) Male, left face of hypopygium. Scale bars: 0.1 mm.

Figure 41. Megaselia manicata. (A) Female, abdominal tergites 5–7. (B) Male, left face of hypopygium. (C) Male, basitarsus of front leg, with two hairs and three spinules enlarged below. Scale bars: 0.1 mm.

Figure 42. Megaselia meigeni. (A) Male, left face of hypopygium. (B) Female, abdominal tergites 5–6. Scale bars: 0.1 mm.

Figure 43. Megaselia minor. (A) Female abdominal tergites 5–7. (B) Male frons, with bristles represented by their basal sockets only (al, anterolateral bristle; an, antial bristle; us, upper supra-antennal bristle). (C) Male, left face of hypopygium. Scale bars: 0.1 mm.

Figure 44. Megaselia nigra male. (A) Anterior face of tip of hind tibia. (B) Left face of hypopygium (p, hooked process of left lobe of hypandrium). Scale bars: 0.1 mm.

Figure 45. Megaselia nigra female. (A) Abdominal tergites 5–7. (B) Dufour’s crop mechanism. (C) Furca. Scale bars: 0.1 mm.

Figure 46. Megaselia oxybelorum male hypopygium. (A) Left face. (B) Right face. Scale bar: 0.1 mm.

Figure 48. Megaselia pleuralis. (A) Female abdominal tergites 5–8. (B) Left face of hypopygium. Scale bars: 0.1 mm.

Figure 49. Megaselia pleuralis. (A) Male, left face of penis complex (P1, P2, left and right paraphyses) and left lobe of hypandrium (H). (B) Female labrum. Scale bars: 0.1 mm.

Figure 50. Megaselia plurispinulosa. (A) Female, abdominal tergites 5 and 6. (B) Left face of male hypopygium. Scale bars: 0.1 mm.

Figure 51. Megaselia ruficornis left face of male hypopygium. Scale bar: 0.1 mm.

Figure 53. Megaselia ruficornis female, details of abdomen. (A) Lobes at rear of sternum 8. (B) Furca from below. Scale bar: 0.1 mm.

Figure 54. Megaselia rufipes male. (A) Left face of an abdominal tergite. (B) Left face of male hypopygium. Scale bar: 0.1 mm.

Figure 55. Megaselia rufipes female, abdomen from above from segment 6 onwards. Scale bar: 0.1 mm.

Figure 56. Megaselia rufipes. (A) Right wing (c, costal cilia, a, bristles of axillary ridge, 1–7, veins 1–7). (B) Female, abdominal tergites 5–7. Scale bars: 0.1 mm.

Figure 59. Megaselia scalaris male. (Drawing by J. W. Rodford.)

Figure 60. Megaselia scalaris. (A) Left face of male hypopygium. (B) Female abdominal tergites 5–7. Scale bars: 0.1 mm.

Figure 63. Megaselia stenoterga. (A) Dufour’s crop mechanism of female. (B) Left face of male hypopygium. (C) Female abdominal tergites 2–6. Scale bars: 0.1 mm.

Figure 64. Megaselia stenoterga right wings. (A) Male (c, costal cilia; A, axillary bristles; 4–7, the thin veins 4–7). (B) Female. Scale bars: 0.1 mm.

Figure 66. Megaselia stichata female. (A) Lobes at rear of abdominal sternum of segment 8. (B) Labrum. (C) Abdominal tergites 5–7. Scale bars: 0.1 mm.

Figure 67. Megaselia striolata. (A,B) Left faces of male hypopygia, from two slightly different angles. (C) Female abdominal tergites 5–7. Scale bars: 0.1 mm.

Figure 68. Megaselia subfuscipes. (A,B) Left faces of male hypopygia, with penis complex withdrawn and extruded. (C) Female abdominal tergites 5–7. Scale bars: 0.1 mm.

Figure 69. Megaselia verralli male. (A) Left face of hypopygium. (B) Right face of lower part of same below anal tube. (C) Posterior face of mid femur. Scale bars: 0.1 mm.

Figure 70. Megaselia species Y female, abdominal tergites 5–7. Scale bar: 0.1 mm.