30 U.S. NATIONAL MUSEUM BULLETIN 244 



2b. Hindtibia with two minute spurs or less. 



4a. Mesothoracic tibia with one or two small apical spurs. 



5a. Costal margin of fore wing with sclerotized stigma (fig. 155). 



7. Naevipenna 

 5b. Costal margin of forewing without stigma. 



6a. Antennae with less than 25 segments; hindtibia without spurs. 



5. Prochalia pygmaea 

 6b. Antennae with more than 26 segments; hindtibia with one or two 

 minute spurs. 

 7a. Hindwing with a basal crossvein present (fig. 167) ; wings usually 

 fully scaled, but in few species nearly transparent. 



19. Oiketicus 

 7b. Hindwing without basal crossvein; wings transparent. 



18. Biopsy che 

 4b. Mesothoracic tibia without spurs. 



8a. Forewing with 11, sometimes 10, veins; discal scales hairlike. 



9a. Wing expanse 25 mm. or more ; antennae vdth more than 25 segments ; 

 hindwing with basal crossvein distinctly present. 



29. Hyalcscotes fumosa 



9b. Wing expanse less than 20 mm. ; antennae with less than 25 segments ; 



hindwing with basal crossvein absent or sometimes indistinctly 



indicated 6. Zamopsyche commentella 



8b. Forewing with 12 veins; discal scales oblanceolate . . . 10. Lumacra 

 lb. Foretibia without an epiphysis. 



10a. Hindtibia with four prominent spurs; 10 veins present in forewing. 



3. Epichnopterix pulla 

 10b. Hindtibia with two minute spurs or less; 10 or more veins in forewing. 

 11a. Mesothoracic tibia with small apical spur. 



12a. Both wings fully scaled; hindwings normally with 8, rarely 7, veins. 

 13a. Wing expanse 26 mm. or less; forewing unicolorous. 



8. Cryptothelea 

 13b. Wing expanse exceeding 30 mm.; forewing not unicolorous, with 



dark discal spot 52. Oiketicus platcnsis 



12b. Wings transparent or nearly so; hindwings normally with 6 or 7, rarely 



8 veins. 



14a. Antennal pectinations abruptly decreasing in length before apex 



(fig. 385), antennae becoming strongly biserrate on outer fourth; 



meso- and metathoracic tibiae with either one or two minute 



apical spurs 20. Tbyridopteryx 



14b. Antennal pectinations gradually decreasing in length to tip of 

 antennae; meso- and metathoracic tibia with one apical spur. 



15a. Forewing with 12 veins 16. Thanatopsyche 



15b. Forewing with 10 or fewer veins 17. Aniniula 



lib. Mesothoracic tibia without spurs. 

 16a. Forewing with 10 veins. 



17a. Antennae serrate 4. Apterona crenulella 



17b. Antennae bipectinate. 



18a. Forewings devoid of scales, transparent; hindwings with outer 



margin greatly extended (fig. 37) . . . 39. Aninuila seitzi 



18b. Forewings thinly scaled; hindwings normal, evenly rounded 



(fig. 31) 33. Coloneura fragilis 



