Rhaphium

Key to male Siberian species of Rhaphium

1 Hind coxa with a group of lateral hairs.................................................................... 2

- Hind coxa with 1 strong lateral seta...................................................................... 24

2 Face black in frontal view, or silver-white in lateral view...................................................... 3

- Face silver-white in both frontal and lateral views........................................................... 9

3 Cercus divided into lobes............................................................................... 4

- Cercus not divided into lobes............................................................................ 6

4 Mid coxa from below lacking spike-like setae. Lower calypter with white cilia. Tarsomere 2 of foreleg with ventral process (Fig. 3 C); fore basitarsus with a row of short black anterodorsal setae. Hypopygium as in Figures 3 A, B, D, with base of sursty- lus sinuous and nearly subequal in length to cercus............................................ R. nasutum (Fallén)

- Mid coxa from below with spike-like setae. Lower calypter with black cilia. Tarsomere 2 of foreleg without ventral process (Fig. 3 I)............................................................................................. 5

5 Length of fore basitarsus more than the length of all others tarsomeres combined; ventrally with row of black setae. Hypopy- gium as in Figures 3 E–F, with short hook-like process base of surstylus.......................... R. commune (Meigen)

- Length of fore basitarsus shorter than length of all others tarsomeres combined; ventrally without row of black setae. Hypopy- gium as in Figuress 3G–H, with surstylus truncate apically bearing crown of dense setae............. R. glaciale Ringdahl

6 Hind tibia distinctly thickened at tip; yellow in basal part, black in apical part. Fore basitarsus not swollen at tip. Hypopygium as in Figures 3 J–K..................................................................... R. fascipes (Meigen)

- Hind tibia not thickened at tip. Fore basitarsus swollen at tip................................................... 7

7 Surstylus very short, thick, slightly longer than wide, in apical part with two processes (Fig. 3 L, M). Apical part of M3+4 longer than dm-cu crossvein. Lower calypter with black cilia........................................ R. boreale Van Duzee

- Surstylus long, clearly longer than wide; in apical part swollen without processes. M3+4 shorter than dm-cu crossvein. Lower calypter with white cilia................................................................................ 8

8 Surstylus curved on ventral side (Figs. 3 N–P). Fore tibia with row of long posteroventral setae, which are longer than width of tibia. Hind basitarsus thickened....................................................... R. jamalensis Negrobov

- Surstylus straight, not curved (Figs. 3 Q–R). Fore tibia without long posteroventral setae. Hind basitarsus not thickened.................................................................................... R. nigribarbatum (Becker)

9 Tarsomere 5 of mid tarsus broadened (Figs. 4 B, G, J)........................................................ 10

- Tarsomeres of mid tarsus not broadened.................................................................. 13

10 Cercus without process, broad, triangular, shorter than epandrium. Tarsomere 4 of midleg slightly broadened at tip, yellow in basal part; tarsomere 5 of midleg broadened, black, elongate oval. Surstylus needle-shaped, curved (Fig. 4 A).............

.................................................................................... R. confine Zetterstedt - Cercus with process, long, ribbon like, longer than epandrium. Mid tarsomeres 4–5 greatly broadened. Surstylus of different shape.............................................................................................. 11

11 Tarsomere 5 of mid tarsus abruptly broadened (Fig. 4 B), considerably wider than long, convex laterally. Hypopygium as in Figures 4 C–E..................................................................... R. latimanum Kahanpää

- Tarsomere 5 of mid tarsus gradually broadened (Figs. 4 J, G), with straight margins................................ 12

12 Cercus with very small appendage at basal third bearing single cilium, with rows of hairs in distal half (Figs. 4 F–I)........................................................................................... R. patellitarse (Becker)

- Cercus forked near middle, with unequal lobes and bunches of hairs at apex of both lobes (Figs. 4 K–M)..................................................................................................... R. crassipes (Meigen)

13 Mid coxa with group of setae forming spike-like prolongation................................................. 14

- Mid coxa with group of setae, not forming spike-like prolongation............................................. 18

14 Cercus divided into two lobes (Fig. 4 N)........................................ R. firsovi Stackelberg & Negrobov

- Cercus not divided into two lobes...................................................................... 15

15 Fore basitarsus not broadened apically. Hypopygium as in Figures 4 O–P......................... R. laticorne (Fallén)

- Fore basitarsus broadened apically..................................................................... 16

16 Fore basitarsus with group of long hairs. Surstylus thickened at apex; cercus with short narrow process at the base (Figs. 4 Q–R)................................................................................. R. rivale (Loew)

- Fore basitarsus without long hairs. Surstylus not thickened at apex; cercus without process at base................... 17

17 Larger: 5.6–6.9 mm. Apical part of surstylus blade-like, pointed (Figs. 5 A–B). Fore basitarsus slightly longer than tarsomere 2................................................................................... R. essoensis Negrobov

- Smaller: 3.6–3.7 mm. Apical part of surstylus elongate-oval, rounded (Figs. 5 C–D). Fore basitarsus more than 1.5X as long as tarsomere 2....................................................................... R. elegantulum (Meigen)

18 Fore femur with row of strong setae ventrally. Hypopygium as in Figures 5 E–F.................... R. riparium (Meigen)

- Fore femur without strong setae ventrally................................................................. 19

19 Cercus not divided into lobes........................................................................... 20

- Cercus divided into lobes.............................................................................. 21

20 Cercus apically broad, with long ventral hook-like process, without bundle of setae (Figs. 5 G–H)....... R. praerosum Loew

- Cercus apically narrow, near top without hook-like process but dorsally with bundle of long dense setae (Figs. 5 I–J)............................................................................................ R. penicillatum Loew

21 Femora yellow, cercus bilobed. Hypopygium as in Figure 5 K.............................. R. nudiusculum Negrobov

- Femora mostly dark; cercus trilobed..................................................................... 22

22 Mid femur and hind tibiae black; stylus shorter than postpedicel; cercus reaching middle of abdominal segment 4 (Figs. 5 L–M).......................................................... R. subtridactylum Negrobov, Barkalov & Selivanova

- Tip of mid femur and basal third of hind tibia dusky-yellow; stylus longer than postpedicel; cercus reaching abdominal seg- ment 3............................................................................................. 23

23 Fore basitarsus longer than tarsomeres 2–5 combined; inner lobe of cercus distinctly longer than epandrium (Figs. 6 A–B)........................................................................................ R. tridactylum (Frey)

- Fore basitarsus as long as tarsomere 2; inner lobe of cercus shorter than epandrium (Fig. C)....... R. dichromum Negrobov

24 Fore basitarsus with row of short strong ventral setae. Hypopygium as in Figure 6 D................. R. micans (Meigen)

- Fore basitarsus without row of short strong ventral setae..................................................... 25

25 Postpedicel small, longer than wide. Hypopygium as in Figures 6 E–F.............. R. beringiense Negrobov & Vockeroth

- Postpedicel long ribbon like, at least 1.5X longer than wide................................................... 26

26 Frons mat, with dense white or brown pollinosity........................................................... 27

- Frons shining, without dusting.......................................................................... 30

27 Legs black. Hypopygium as in Figures 6 G–H.......................... R. sibiricum Negrobov, Barkalov & Selivanova

- Legs partly or completely yellow........................................................................ 28

28 Postpedicel length 8X its width. Fore femur dorsally and hind femur at tip dark..................... R. borisovi sp. nov.

- Postpedicel length 5– 6 X its width. All femora yellow....................................................... 29

29 Inner lobe of cercus approximately 1.5– 2 X as long as epandrium; outer lobe of cercus approximately 6X shorter than inner lobe (Figs. 6 I–K). Fore tibiae and tarsomeres 1–2 of foreleg with row of short erect ventral setae … R. grandicercum Negrobov

- Inner lobe of cercus slightly longer than epandrium; outer lobe of cercus long, slightly shorter than inner lobe (Figs. 7 A–B). Fore tibiae and taromeres 1–2 of fore tarsus without short erect ventral setae.................... R. albifrons Zetterstedt

30 Hind coxa with pale seta.............................................................................. 31

- Hind coxa with dark seta.............................................................................. 32

31 Postpedicel 6X as long as wide; stylus 1.5– 2 X longer than width of postpedicel. Surstylus narrow rectangular, at top with deep notch and long ventral process (Figs. 7 C–D).................................................... R. fissum Loew

- Postpedicel 7X as long as wide; stylus slightly longer than width of postpedicel. Surstylus broadly triangular, without notch and ventral process (Figs. 7 E–F)....................................................... R. gruniniani Negrobov

32 Cercus with long apical seta (Figs. 7 G–H)................................................ R. monotrichum Loew

- Cercus without long apical seta......................................................................... 33

33 Cercus with tuft of long setae (Figs. 7 I–J)................................................ R. caliginosum Meigen

- Cercus without tuft of long setae......................................................................... 34

34 Cercus short oval (Figs. 7 K–M). Postpedicel approximately 4X as long as wide.................... R. lanceolatum Loew

- Cercus narrow, thread-like (Figs. 7 N–O). Postpedicel approximately 5X as long as wide............. R. umbripenne (Frey)