March, 1917.] FoRBES : HydRIOMENIN^ OF THE UNITED StATES. 49 



14. Hind tibiae with both pairs of spurs 16 



15. With a single small accessory cell on anterior side of discal cell distinctly 



before its end ; hind wing with Sc and R only shortly fused, but cell 

 closed by a nearly transverse mdcv Synomila (19). 



15. Accessory cell reaching end of discal cell, often with Mj arising from it; 



fusion of Sc and R in hind wing long Gymnoscelis (20). 



16. Front rounded out half the width of the eyes or more (usually obliquely), 



close-scaled ; small species with single ace. cell, and slight dorsal ab- 

 dominal tufts like Eupithecia Nasusina (21). 



16. Front less strongly rounded out, when most prominent {Venusia, etc.) 



moths of entirely different appearance 17 



17. Rj running directly across from ace. cell, to Sc, like a cross-vein, the tip 



occasionally free Chloroclystis (22). 



17. Ri free after leaving ace. cell (as a rare aberration very shortly fused 



with Sc) 18 



18. A tuft near inner margin of hind wing, opposite end of abdomen 19 



18. No such tuft, the hind wing in our species not sexually modified 20 



19. Tuft black and very conspicuous, covering a hyaline patch ; wings less 



deeply scalloped, male claspers normal Calocalpe (23). 



19. Tuft fuscous and less specialized; end of abdomen broad with large clasp- 



ers and specialized tufting ; the wings more deeply scalloped. 



Coryphista (24). 



20. Fore wing with a hair-pencil on under side near base 21 



20. No hair-pencil on fore wing 23 



21. Mdcv. of hind wing in our species short and straight, wings bluntly rounded. 



Polythrena (25). 



21, Mdcv. long and bent ; wings acute at apex Lygris (26). 



22. Hind wings deeply scalloped, the tooth of M^ about as strong as any. 



Triphosa (27). 



22. Hind wings with at most a somewhat wavy margin 23 



23. Middle discocellular of hind wing long and bent 24 



23. Mdcv. no longer than lower, and straight 28 



24. Antennae unipectinate Monotaxis (28). 



24, Antennae bipectinate, serrate or simple 25 



25. Front rounded and quite smoothly scaled, usually full as wide as eyes, 



curving in below to clypeus, the palpi hardly exceeding it 26 



25. Front at least rough scaled below, generally, and always when wider than 



eyes with a distinct conical tuft Hydriomena (series I) (37). 



26. Two accessory cells, antennje laminate, wings bluntly rounded, black and 



red (Enotrus (29). 



26. Two accessory cells, wings more pointed, with simple markings above (the 



ground color most often yellow) and complexer below ; practically all 



with laminate antennae Stamnodes (30). 



26. Antennae various, accessory cell sometimes single, markings complex on a 



gray or white ground above, simpler below 27 



