Usia, Latreille, 1802

Gibbs, David, 2011, 2960, Zootaxa 2960, pp. 1-77 : 13-18

Key to species of Usia subgenus Micrusia Evenhuis and Usia versicolor Fabricius

As with most parasitoid insects, Usiini can be exceptionally variable, some being several times the size of the smallest. Such large discrepancies in size can often be accompanied by differences in proportions, width of frons, density of dusting, hairiness, surface sculpture and many other minor variations. While every effort has been made to avoid the more variable characters, there will always be specimens that will not run cleanly through a key or may even run to the wrong species. If in any doubt, it is essential to dissect and examine the male and/or female genitalia. Even this precaution might not be adequate for some females. Such specimens collected outside of an expected range and/or without associated males should be treated with extreme caution.

1 Males ............................................................................................... 2

- Females............................................................................................ 23

2 At least some ventral hairs on at least one pair of femora outstanding and longer than median width of tibia ( Fig. 7), in some species, particularly U. ignorata , these can be inconspicuous and easily lost, most readily seen on mid-femur posteroventrally ( Fig. 8).............................................................................................. 3

- Ventral hairs of femora usually adpressed and not longer than median width of tibia ( Fig.9).......................... 12

3 Mesonotum and dorsum of abdomen covered with dense brown dust obscuring black ground colour, becoming more orange on middle of abdomen. Mid-tibia with short, suberect black bristles apicoventrally. Genitalia diagnostic (Plate XXII a-d)...... 4

- Mesonotum and dorsum of abdomen largely shining black with dusted areas limited and not obscuring the black ground colour. Mid-tibia apicoventrally without suberect black bristles, just normal closely adpressed setae..................... 5

4 Proboscis furnished laterally with long bristly hairs, longest as long as width of labium ( Fig. 10).......................................................................................... ♂ versicolor (Fabricius) ( Europe & Algeria)

- Proboscis furnished with significantly shorter, stubbly hairs, longest no longer than width of labium ( Fig. 11)......................................................................... ♂ versicolor (Fabricius) ( Atlas Mountains , Morocco)

Close examination of genitalia and often dissection needed from here on.

5 Epandrium with apical or sub-apical elongations, usually longer than wide but in some forcipata much reduced, in pinned material often folded round cerci (Plate XII e,f, Plate IX e,f & Plate XI e,f)........................................ 6

- Apical corners of epandrium rounded or roundly angular, not narrow and elongated (e.g. Plate XIII f & Plate XV f)........ 8

6 Epandrial elongations sub-apical, usually with much shorter point in more apical position (Plate XI e,f). Wing darkened basally. Gonocoxite and aedeagus as in Plate XI a–f. The Balkans................................. ♂ forcipata Brullé

- Epandrial elongations at apical corners without small point between them and mid-line of epandrium (Plate IX e,f). Wings not basally darkened. Gonocoxite and aedeagus not as above....................................................... 7

7 Epandrial elongations slender, parallel sided (Plate IX f). Tergites basally and laterally lightly grey dusted. Gonocoxite and aedeagus as in Plate IX a–f. Spain........................................................ ♂ engeli Paramonov

- Epandrial elongation triangular, sides converging to a rounded point (Plate VII f). Tergites without conspicuous dusting. Gonocoxite and aedeagus as in Plate VII a–f. North Africa. ....................................... ♂ dilsi Gibbs sp. nov .

8 Frons relatively wide, wider than distance across lateral ocelli, lateral ocelli separated from eye-margin by about their diameter ( Fig. 12)............................................................................................. 9

- Frons relatively narrow, narrower than distance across lateral ocelli, lateral ocelli very close to eye-margin separated by less than their diameter ( Fig. 13)............................................................................ 11

9 Knob of haltere infuscated. Gonostyli often exposed, S-shaped (Plate XV c). Epandrium relatively small, quadrate; gonocoxite and aedeagus as in Plate XV a–d. [Frons and mesonotum wrinkled but shining]. The Balkans............ ♂ novakii Strobl

- Knob of haltere white or pale yellow. Gonostyli not S-shaped. Epandrium longer, almost as long as abdomen............ 10

10 Mesonotum and scutellum shagreened, matt, texture distinctly different along paramedian lines. Ventral femoral hairs slightly longer than width of tibia. Gonocoxite and aedeagus as in XIII a–f............................ ♂ hyalipennis Macquart

- Mesonotum and scutellum shining, at most somewhat wrinkled, paramedian lines not clearly differentiated. Ventral femoral hairs (when present; easily lost in this species) as long as width of femora. Gonocoxite and aedeagus as in XIV a–f............................................................................................... ♂ ignorata Becker

11 Mesonotum conspicuously grey-dusted along acrostichal and dorsocentral lines and on front of thorax between front of dorsocentral line and postpronotal lobe. Gonocoxite with apicomedial ‘horns’ often visible in pinned specimens (Plate XIX a–e)..................................................................................... ♂ syriaca Paramonov

- Mesonotum smooth and shining between hair insertions, almost undusted. Gonocoxite lacking apicomedial ‘horns’ (Plate VIII a–f)............................................................................ ♂ echinus Gibbs sp. nov.

Close examination of genitalia and often dissection needed from here on.

12 Hairs short, those on margin of scutellum barely longer than half length of scutellum (measured from suture to apex) Fig. 14. ( U. cryptocrispa might run here; if with wavy-tipped hairs on epandrium and scutellar hairs not clearly short go to couplet 16) ................................................................................................... 13

- Longer haired species, those on margin of scutellum about as long as length of scutellum or longer Fig. 15; if shorter ( U. cryptocrispa ) then epandrium clothed with wavy-tipped hairs.............................................. 16

13 Genitalia folded under abdomen with disc of epandrium pressed against sternites. Epandrium quadrate or transverse with relatively long apical hairs. African species................................................................... 14

- Genitalia with epandrium at right angles to sternites. Epandrium longer than broad with very short setae. European species...................................................................................................... 15

14 Mesonotum and scutellum smooth and shining. Epandrium quadrate with lateral extensions that, in pinned specimens, fold round cerci. Gonocoxite and aedeagus as in Plate XXI a–f. Algeria........................... ♂ turaco Gibbs sp. nov .

- Mesonotum and scutellum with rough shagreened matt surface, at least on scutellum and adjacent parts of mesonotum. Epandrium large, transverse and globular with long wavy apical hairs. Gonocoxite and aedeagus as in X a–f. Morocco........................................................................................... ♂ falcata Gibbs sp. nov .

15 Mesonotum with rough shagreened texture, matt, no more than dull shine, hair insertions largely effaced. Gonocoxite oval, globular, gonostyli extending well beyond tip of gonocoxite (PlateXVII a–e). France, Spain............. ♂ pusilla Meigen

- Mesonotum, while often finely transversely striated or wrinkled, still shining with hair insertions clear. Gonocoxite elongate, small gonostyli hardly extending beyond tip of gonocoxite (Plate XVIII a–e). Spain............. ♂ susanae Gibbs sp. nov .

16 Gonocoxite medially with converging appendages tipped with brush of hairs, usually visible in caudal view (Plate III c & Plate VI c). Tip of aedeagus with looped structure furnished with dark spines (Plate III a,b & Plate VI a,b)................... 17

- No such appendages on gonocoxite....................................................................... 18

17 Tip of ejaculatory duct with protuberance immediately below (Plate III b). Gonocoxite as in Plate III c–d. Israel............................................................................................. ♂ carmelitensis Becker

- Tip of ejaculatory duct distinctly separated from protuberance below it (Plate VI b). Gonocoxite as in Plate VI c,d. Tunisia..................................................................................... ♂ dahli Gibbs sp. nov .

18 Epandrium with apical elongations, in pinned material often folded round and enclosing cerci ( Fig. 16 & Fig. 17); if in doubt then epandrium practically hairless on disc. Israel........................................................... 19

- Apical corners of epandrium with small points or protrusions not evident in dry material, any larger protrusions well removed from tip of epandrium. Epandrium clearly pubescent (e.g. Plate IV f). Morocco................................... 20

19 Basal lobes of gonocoxite transverse in dorsal view, dividing sulcus not deep, when viewed from above two halves form an almost smooth arc with only shallow medial interruption ( Fig. 18). Epandrium relatively short, clearly pubescent on disc, in dorsal view constricted medially with long rounded (semiclavate) extensions directed apically. Aedeagus as in Plate XX a–f.................................................................................. ♂ theodori Gibbs sp. nov.

- Basal lobes of gonocoxite elongate in dorsal view, dividing sulcus strongly developed, when viewed from above two halves form two almost separated hemispheres deeply divided medially ( Fig. 19). Epandrium elongate, hairless on disc, not medially constricted in dorsal view with broader, more pointed apical extensions. Aedeagus as in Plate II a–f................................................................................................... ♂ biconvexa Gibbs sp. nov.

20 Anepisternum shining, undusted on central part. Tergites shining, no sign of dusting on disc......................... 21

- Anepisternum dusted on central part, shining along posterior margin. Tergites obscurely dulled by dusting basally on disc.. 22

21 Frons wider than length of third antennal segment. Mesonotum smooth and shiny, somewhat wrinkled. Genitalia exceptionally large, globular, almost as large as thorax, epandrium strongly domed, almost hemispherical. Gonocoxite and aedeagus as in Plate XII a–f. Morocco........................................................... ♂ globicauda Gibbs sp. nov .

- Frons narrower than length of third antennal segment. Mesonotum with rough texture, matt, especially in hind half and on scutellum. Genitalia much less conspicuous, apex of epandrium densely clothed with wavy-tipped hairs (not to be confused with hairy cerci). Gonocoxite and aedeagus as in Plate IV a–f. Morocco........................ ♂ crispa Gibbs sp. nov .

22 Tergites decidedly matt due to dense tuberculate surface sculpture. Frons about one fifth head width. Shorter haired, ocellar hairs shorter than width of frons. Gonocoxite with median horn surmounted by dense tuft of dark hairs (only visible with difficulty in dry specimens). Genitalia (Plate V a–f)....................................... ♂ cryptocrispa Gibbs sp. nov.

- Tergites shining with more widely separated transverse wrinkles. Frons about one quarter head width. Longer haired than above, ocellar hairs about as long as width of frons. Gonocoxite without tufted horn medially (Plate XVI a–f)........................................................................................... ♂ paracrispa Gibbs sp. nov.

23 At least some ventral hairs on at least one pair of femora longer than median width of tibia (see Fig. 7 & Fig. 8)......... 24

- Ventral hairs of femora usually adpressed, not longer than median width of tibia ( Fig. 9)............................ 32

24 Disc of mesonotum entirely or partially dusted, enough to render matt but not to obscure ground colour. At least median and dorsocentral lines grey dusted........................................................................... 25

- Disc of mesonotum largely undusted, any dusting limited to the margins, either shining black or more rarely shagreened matt. ................................................................................................... 26

25 Mid-tibia with outstanding spine-like bristles ventrally on about apical quarter. Mesonotum uniformly dusted, tergites often dusted, especially laterally. Genitalia as in Plate XXII e,f....................................................... ♀ versicolor (Fabricius) ( Europe , Algeria, Tunisia; and Atlas Mountains, Morocco) [the two populations not separable in this sex]

- Mid-tibia lacking outstanding spine-like bristles ventrally at tip. Mesonotum conspicuously dusted leaving shining black paramedian and antehumeral vittae, abdomen shining. Genitalia as in Plate XIX f,g.................... ♀ syriaca Paramonov

External characters variable so dissection often needed for reliable identification from here on.

26 Wing darkened basally. Apical sternite as in Plate XI g, h. The Balkans............................. ♀ forcipata Brullé

- Wing clear.......................................................................................... 27

27 Mesonotum matt, shagreened (Plate XIII g,h)............................................ ♀ hyalipennis Macquart Mesonotum no more than wrinkled, smooth and shining not shagreened......................................... 28

28 Apical sternite longer than wide, flat, with basal unsclerotised ‘window’. Proximal part of furca transparent (Plate IX g,h). Spain............................................................................... ♀ engeli Paramonov

- Apical sternite of different form, fully sclerotised, not flat. Proximal part of furca pigmented......................... 29

29 Frons wider, about one-fourth head width ( Fig. 20) [Anepisternum entirely or largely dusted, shining cuticle only apparent around margins of sclerite]............................................................................. 30

- Frons narrower, about one-fifth head width ( Fig. 21) [Anepisternum shining or dusted]............................. 31

30 Penultimate sternite normally haired, hind half with evenly distributed hairs in 2–3 irregular rows. Shorter haired species, ventral hairs on mid femora only a little longer than greatest depth of that femur. Ocellar hairs hardly longer than distance across lateral ocelli. Apical sternite almost square, with rounded boss basally and apically notched, this apical notch margined with silvery dust visible as a “V” in dry specimens (Plate XV h). Tip of furca rather irregular, ‘knobbly’, arms set at right angles (Plate XV g). The Balkans to Israel.......................................................... ♀ novakii Strobl

- Penultimate sternite with hairs on hind half clumped medially to form more or less conspicuous tuft (Plate XIV h). Longer haired species, ventral hairs on mid femora about 1.5 times longer than greatest depth of that femur. Ocellar hairs longer than distance across lateral ocelli. Apical sternite rectangular, without rounded boss basally, but rather transparent in this part. Apical notch of different form without silvery dust. Tip of furca rather pointed, arms set in line with main part (Plate XIV g,h). Tunisia to Israel......................................................................... ♀ ignorata Becker

31 Anepisternum entirely shining or with thin dusting giving greasy appearance. Apical sternite longer than broad, with transverse fold or ridge just basal to midline. Transverse ridge often visible in dry specimens as scarp, suddenly dropping away proximally, cuticle on proximal side shining, undusted. Genitalia as in Plate VIII g,h............ ♀ echinus Gibbs sp. nov.

- Anepisternum either mostly shining with ventromedial dusted patch or entirely dusted. Apical sternite wider than long, with basal bulge or boss. Boss usually visible in dry specimens, proximal slope finely coated with minute setulae creating silvery sheen. Genitalia as in Plate VII g,h....................................................... ♀ dilsi Gibbs sp. nov.

External characters variable so dissection often needed for reliable identification from here on.

32 Hairs short, those on margin of scutellum hardly longer than half length of scutellum ( Fig. 14). Tip of furca never with double curve.............................................................................................. 33

- Longer haired species, those on margin of scutellum about as long as length of scutellum or longer ( Fig. 15) (longer hairs can get knocked off and U. cryptocrispa can have marginal hairs barely half median length of scutellum, this species with tip of furca double curved (Plate V h))......................................................................... 36

33 African species. Apical cleft of last visible sternite narrowly V-shaped, significantly narrower than apical processes...... 34

- European species. Apical cleft of last visible sternite U-shaped, as wide or wider than apical processes................. 35

34 Furca with tip pointed and pigmented. Last visible sternite with subapical translucent window (Plate XXI g,h). Mesonotum relatively shining, wrinkled............................................................. ♀ turaco Gibbs sp. nov.

- Furca with pigmented areas confined to base and arms, tip transparent, rounded (Plate X g). Last visible sternite without obvious translucent subapical window (Plate X h). Mesonotum subshining, disc decidedly shagreened... ♀ falcata Gibbs sp. nov.

35 Mouth margin narrower ( Fig. 22). Last visible sternite pigmented sub-apically, although there can be longitudinal fold in this area (Plate XVIII g). Mesonotum, especially anteriorly, relatively shining although usually wrinkled, with clear hair insertions. Tip of furca pointed, pigmented (Plate XVIII f).......................................... ♀ susanae Gibbs sp. nov.

- Mouth margin broader ( Fig. 23). Last visible sternite with apicomedial V-shaped transparent area (forms clear longitudinal fold in dry specimens), usually two translucent windows either side (Spanish specimens XVII h) OR last visible sternite as in U. susanae (Plate XVIII g); tip of furca rounded, transparent (single French specimen Plate XVII f)....... ♀ pusilla Meigen

36 Apical sternite large, domed, with no more than shallow apical notch. Proximal part of furca membranous or represented by a few pigmented patches................................................................................ 37

- Apical sternite smaller, not domed but with basal boss, with distinct apical notch. Proximal part of furca may be membranous but clearly present and complete......................................................................... 38

37 Vaginal plate pear-shaped, darkly pigmented, distal arms of furca short or absent, apical sternite strongly domed, apical processes longer (Plate III f,g). Israel....................................................... ♀ carmelitensis Becker

- Vaginal plate longer, parallel sided and lightly pigmented, distal arms of furca long, apical sternite strongly domed, apical processes hardly protruding beyond curve of sclerite (Plate VI f,g). Tunisia & Algeria................ ♀ dahli Gibbs sp. nov .

38 Scutellum and adjacent parts of mesonotum with rough, shagreened surface sculpture rendering it dull and matt. Tip of furca dark pigmented and coming to point; arms of furca falcate, set at 90º to the main part (e.g. Plate V g).................. 39

- Scutellum and adjacent parts of mesonotum smooth and shining or with wrinkled surface, shining or only slightly dulled by dust. Tip of furca either unpigmented or with rounded tip, if arms of furca falcate, then set approximately in line with main part (e.g. Plate XX g). Israel................................................................................ 41

39 Mesonotum usually more generally matt, little contrast between anterior and posterior parts in nature of surface sculpture. Confluence of basal spermathecal ducts simple, no expanded vaginal plate. Tip of furca curved dorsally as usual, not recurved at extreme point (Plate IV g)........................................................... ♀ crispa Gibbs sp. nov.

- Mesonotum with distinct discrete patch of rough surface sculpture in posterior part of mesonotum adjacent to scutellum, contrasting with more smooth and shining anterior part of mesonotum. Confluence of basal spermathecal ducts expanded into clear oval, vaginal plate, pigmented laterally, transparent centrally (Plate V g, Plate XVI g). Tip of furca curved dorsally as usual then (in most specimens) distinctly recurved at extreme point (Plate V h, Plate XVI h)......................... 40

40 Longer haired species, acrostichals biserial, as long as bare paramedian lines. Many mesonotal hairs longer than separation of eyes at vertex. Apical sternite, vaginal plate and furcal arms different, these are potentially variable characters as very few specimens available (Plate XVI g–i)................................................. ♀ paracrispa Gibbs sp. nov.

- Shorter haired species, acrostichals irregularly biserial, not easily seen, no longer than width of bare paramedian lines and decidedly shorter than separation of eyes across vertex. Apical sternite, vaginal plate and furcal arms different, these are potentially variable characters as very few specimens available (Plate V g–i).................... ♀ cryptocrispa Gibbs sp. nov.

41 Anepisternum shining, undusted. Tip of furca rounded, lightly pigmented, arms short and straight, apical sternite almost rectangular with rather weak apical notch (Plate XII g,h). Morocco........................... ♀ globicauda Gibbs sp. nov .

- Anepisternum entirely or largely dusted. Tip of furca either pointed and transparent or rounded and lightly pigmented, if latter then arms clearly curved and apical sternite of different shape and with distinct apical notch. Israel.................... 42

42 Tarsi as long as tibia. Apical sternite with strong rounded boss basally, usually visible in pinned specimens. Cerci normal. Furca with rounded, lightly pigmented tip and curved arms. Last sternite of characteristic shape (Plate XX g,h)............................................................................................ ♀ theodori Gibbs sp. nov.

- Tarsi shorter than tibia. Apical sternite with a strong basal ridge, decidedly steep sided proximally, usually visible in pinned specimens. Cerci large, rhomboid, shining, clearly visible in most pinned specimens. Furca with pointed, transparent tip strongly contrasting with heavily sclerotised basal part and arms (Plate II g,h). Last sternite of characteristic shape (Palte II i,j).............................................................................. ♀ biconvexa Gibbs sp. nov.