Key to species of Stachia
1 Postantennal organ with four lobes ................................................................................................................................ ......................................................... S. tasgola Bernard, 2008 (described from USA, North Carolina and Michigan)
- Postantennal organ with three lobes ............................................................................................................................. 2
2 Unguiculus present on legs ......................................................................................................................................... 3
- Unguiculus absent on legs ............................................................................................ S . folsomi (Arlé, 1968) (Brasil)
3 Setae a1 present on Abd. I–IV ...................................................................................................................................... 4
- Setae a1 absent on Abd. I–IV........................................................................................................................................ 5
4 Postantennal organ with pointed lobes, femora with three setae each ........... S. minuta Folsom, 1932 (USA, Hawaii)
- Postantennal organ with rounded lobes, femora with larger number of setae .......................... S. oregonensis sp. nov.
5 Dens and mucro separate, mucro with lamella .......................... S . xicoana (Palacios– Vargas & Najt, 1985) (Mexico)
- Dens and mucro fused, mucro not lamellate............................................................ S. populosa (Selga, 1963) (Spain)