[modified from Chvála (2005)]
1 Occiput dull grey or brownish-grey, not black from any point of view............................................ 2
- Occiput dull black, at least from some points of view........................................................ 4
2 Legs mostly yellow.................................................................................... 3
- Legs uniformly black................................................................. H. clavidipes Chvála
3 Acrostichals very small, hair-like, anteriorly uni-serial. Tarsomere 2 on foreleg with long dorsal bristles … H. clavipes (Harris)
- Acrostichals not much smaller, hair-like and bi-serial. Tarsomere 2 on foreleg without long dorsal bristles. H. regnealai Parvu
4 Fore basitarsus shorter than fore tibia. Tarsomere 2 on foreleg without long dorsal bristles........................... 5
- Fore basitarsus as long as or longer than fore tibia. Tarsomere 2 on foreleg with long dorsal bristles.................... 6
5 Legs completely black, only knees narrowly yellowish. Fore basitarsus (Fig. 1) with long dorsal bristles on apical half. Wings brownish............................................................................. H. deryae sp. nov.
- Legs extensively yellowish. Fore basitarsus with long bristles along entire dorsal surface. Wings almost clear, with very faint greyish-brown clouding.................................................................. H. cilipes Meigen
6 Fore tibia with long dorsal bristles, legs completely black or at least only fore coxa and base of fore femur usually yellowish..................................................................................................... 7
- Fore tibia without dorsal bristles, legs dark brown to blackish-brown............................. H. balearica Chvála
7 Legs completely black. Fore basitarsus clearly longer than fore tibia, with 2–4 long serial dorsal bristles................................................................................................. H. bolkarensis Çiftçi et al.
- Legs extensively blackish, only fore coxa and base of fore femur usually yellowish. Fore basitarsus as long as fore tibia, with uni-serial long dorsal bristles............................................................... H. curtisi Collin