TABLE 2. Checklist of the aquatic macroinvertebrates of the Tongue River (t) 



and the Yellowstone River (y). 



Phylum Arthropoda 

 Order Ephemeroptera 

 Family Siphlonuridae 

 y Ameletus (oregonensis McD.?) 



y Isonychia (sicca campestris McD.?) 



Family Baetidae 

 y t Baetis insignificans McD. 

 y t Baetis parvus Dodds 

 y Baetis (propinquus Walsh) 



y Baetis tricaudatus Dodds 



y Centroptilum sp. A 



y t Dactylobaetis cepheus Traver & Edmunds 

 y Pseudocloeon sp. A 



Family 01 igoneuriidae 

 y Lachlania powelli Edmunds 



Family Heptageniidae 

 y Epeorus (Iron) albertae (McD.) 



y Epeorus (Iron) longimanus (Eaton) 



y Heptagenia elegantula (Eaton) 



y t Rhithrogena undulata (Bks.) 

 y t Stenonema terminatum (Walsh) 

 y Stenonema prob n. sp. 



Family Ametropodidae 

 y Ametropus (neavei McD.)? 



Family Leptophlebiidae 

 y t Choroterpes albiannulata McD. 

 y t Leptophlebia gravastella Eaton 

 y Paraleptophlebia bicornuta (McD.) 



y Paraleptophlebia heteronea (McD.) 



y t Traver ella albertana (McD.) 



Family Ephemerel 1 idae 

 y Ephemerella (Attenuatella) margarita N. 



y Ephemerella (Caudatella) h. heterocaudata McD. 



y Ephemerella (Caudatella) hystrix Traver 



y Ephemerella (Drunella) doddsi Needham 



y Ephemerella g. grandis Eaton 



y t Ephemerella (Ephemerella) inermis Eaton 

 y Ephemerella (Serratella) tibialis McD. 



y Ephemerella (Timpanoga) h. hecuba (Eaton) 



Family Tricorythidae 

 y t Tricorythodes minutus Traver 

 y Tricorythodes sp. A 



Family Ephemeridae 

 y Ephemera sp. A 



Family Polymitarcidae 

 y Ephoron album (Say) 



Family Caen idae 

 y t Brachycercus (prudens McD.?) 

 y Caenis latipennis 



32 



