Tolmerus

Broek, Reinoud Van Den, Smit, John T., Bree, Elias De & Beentjes, Kevin, 2018, Tolmerus calceatus (Meigen) confirmed as a valid species separate from Tolmerus atricapillus (Fallén) (Diptera: Asilidae), Zootaxa 4508 (2), pp. 249-258 : 257

Key to the northwestern European Tolmerus -species

The key is largely based on Van den Broek & Schulten (2017). In NW Europe Tolmerus can be separated from Machimus by the relative small size (9–18 mm vs 15–28 mm), the reduced number of scutellar marginal bristles ( Tolmerus : 2–4, rarely 6, Machimus : 6–8). From Neoepitriptus it can separated by the absence of bristles on ventral side the fore femora and on sternites.

1 Femora and tibiae entirely black.............................................................. T. atripes Loew - Femora black with red markings, tibiae red with black markings................................................ 2 2 Fore and mid tibiae red with a distinct black spot in the middle and apically black................................... - Tibia red with black markings but no distinct spot in the middle................................................. 4 3 Femora black with an apical red ring and a full red stripe posteriorly.......................... T. cingulatus (Fabricius) - Femora black with only an subapical red ring................................................. T. cowini (Hobby)

For the following species only males are keyed, for females are very difficult to identify without their accompanying males.

4 Hind margin of the 8th sternite with a forked projection....................................................... 5

- Hind margin of the 8th sternite straight..................................................................... 6

5 Dark, grayish brown to brown species. Hair on frons black, postocular bristles mostly black. Mystax largely black, only in lower third white to yellowish bristles. Longer hairs between dorsocentral bristles in prescutellar area black, long hairs on dorsal side anepisternum black. Fore femora black, usually only the posterior apical half red............ T. atricapillus (Fallén)

- Brown to golden brown species. Hair on frons white, postocular bristles mostly reddish. Mystax in top half black, lower half reddish. Longer hairs between dorsocentrals in prescutellar area white, long hairs on dorsal side of anepisternum white. Fore femora black, always with a full red stripe on the posterodorsal side............................ T. calceatus (Meigen)

6 Mystax black in top half, white in lower half. Legs very variable in colour, femora sometimes entirely black but usually with a red spot just before the apex on anterior side and more or less red in the apical half posteriorly. Hypopygium red, epandrium bent halfway, apically somewhat pointed. Gonopod with 3 black bristle like hairs. Small species 9–14 mm ...................................................................................................... T. pyragra (Zeller)

- Mystax black, only in lower third white bristles. Femora black, posteriorly with a full red stripe. Hypopygium reddish to black, epandrium shaped differently. Medium sized brown T. species, 12–16 mm ........................................ 7

7 Hypopygium dark brown to reddish. Epandrium almost straight, a little widened apically. Gonopod with black hair.............................................................................................. T. micans (Meigen)

- Hypopygium blackish brown. Epandrium short, broad and somewhat rounded apically. Gonopod with white hair.................................................................................................. T. strandi (Duda)