(incomplete described H. aethiopicus (Cooreman, 1951) is not included)
1. Tarsus I with 2 solenidia, genua II–IV with 4 - 4-5 setae, respectively............................................ 2
- Tarsus I with 1 solenidion, genua II–IV with 3 - 3 - 2 setae, respectively......................................................................................... H. arnoldii Livshits and Mitrofanov, 1973. Russia (Crimean peninsula)
2. Solenidion on tibia IV present........................................................................... 3
- Solenidion on tibia IV absent........................................................................... 6
3. Hysterosoma with 1 midsternal plate between coxal fields II and III............................................ 4
- Hysterosoma with 3 midsternal plates between coxal fields II and III... H. johnstoni Atyeo and Baker, 1964. North America
4. Setae f distinctly longer than e........................................................................... 5
- Setae e and f subequal....................................... P. longispinus Atyeo and Baker, 1964. North America
5. Setae f very long, more than 2 times longer than e and reaching beyond posterior margin of body, solenidion on tarsus II very long, reaching tips of claws........................... H. atomarius (Berlese, 1913). Southern Europe, North America
- Setae f much shorter, about 1.5 times longer than e and not reaching posterior margin of body, solenidion on tarsus II reaching only tip of tarsus....................................... H. americanus Delfinado and Baker, 1974. North America
6. Solenidion ω 1 distinctly longer than ω 2.................................................................... 7
- Solenidion ω 1 distinctly shorter than ω 2....................................................................................................... H. sogdianicus Barilo and Sharipov, 1987. Middle Asia (Uzbekistan, Turkmenistan)
7. Setae 4 a and ag 1 situated on plates....................................................................... 8
- Setae 4 a and ag 1 situated on soft striated cuticle.... H. fereshtae Amin, Khanjani and Ueckermann, 2014. Middle Asia (Iran)
8. Solenidion ω 1 not reaching beyond tip of tarsus, tarsus I with 13 setae … H. pickardi Smiley and Moser 1968. North America
- Solenidion ω 1 distinctly reaching beyond tip of tarsus, tarsus I with 14 setae.............................................................................................. H. magnificus Khaustov sp. nov. Western Siberia (Russia)