LEPIDOPTERA OF NEW YORK AND NEIGHBORING STATES 47 



22. M 2 distinctly associated with radial stem, in one, and usually in both wings; 



lower discocellular vein often obsolete; with at least a trace of a humeral 

 vein 24 



23. A humeral vein in hind wing Erycinidae (p. 44) 



23. No humeral vein Lycaenidae (p. 44) 



24. Butterfly walking on four legs (except female of Hypattis), radius five- 



branched; M t from cell Nymphalidae (p. 44) 



24. Butterfly using all its legs for walking; radius usually four-branched, M! 



stalked with it Pieridse (p. 44) 



25. Lorth American species very stout, and with wings 55 mm. (two inches) 



or more in expanse; the hina wings rarely reaching beyond middle of 

 abdomen ; Sc and R of hind wing connected at the middle of the cell or rather 

 before by a vein (RJ which is as strong as any; and then closely parallel 

 to end of cell or beyond Sphingidae (p. 42, 360) 



25. Wings proportionately larger; Sc and R rarely connected by a strong cross 



vein, and if so, strongly divergent beyond it (fig. 426) 26 



26. Sc and R separate, but connected by a more or less distinct cross vein; acces- 



sory cell fused with discal cell, but with the line of separation (Rj+is) indi- 

 cated by a slight thickening starting from an angulation in the stem of 

 R; species under 30 mm. in expanse (fig. 155) A few Micros.. 59 



26. Accessory cell separated by a full-sized vein, or completely absent 27 



27. Cu of fore wing apparently three -branched (in a couple of Lithosians two- 



branched) , . .28 



27. Cu of fore wing apparently four-branched 42 



28. Frenulum normal 29 



28. Frenulum rudimentary (less than one-fifteenth length of hind wings) or 



absent 35 



29. Sc and R fused from base of hind wing beyond middle, then rapidly diverging; 



swollen at the base; slender moths Lithosiidse in part (p. 42) 



29. Sc and R separate at extreme base; then closely approximate or fused a 

 greater or less distance ' 30 



29. Sc and R sharply divergent from close to base (fig. 409) . . Epiplemidae (p. 654) 



30. Hind wing with Sc angled near base, connected by a strong cross vein to 



humeral angle Most Geometridae (p. 41) 



30. Sc of hind wing moderately curved or straight at base 31 



31. Hind wing with Cu apparently 4 -branched, M 2 being much nearer M s than MI; 



Sc and R closely parallel beyond end of cell; vestiture deep (fig. 432). 



Thyatiridas (p. 686) 



31. Hind wing with Cu apparently 3-branched, M 2 being as near to Mj as to M 3 ; 



Sc and R separating before end of cell (fig. 425) 32 



32. Stout species ; no tympanic hood; 1st A lost 33 



32. Usually slender species; when rather stout, with a well-marked lateral hood 



on first segment of abdomen 34 



33. Tongue absent; fore wing with R, and R 3 , R 4 and Rj stalked together (fig. 425) ; 



northern species with hyaline dots on fore wing 



Eupterotidae (Apatelodes) (p. 678) 



33. Tongue present, often weak; fore wing fully scaled; usually with accessory 



cell, or R 3 and R, long-stalked together Notodontidae (p. 42, 678) 



34. Subcosta straight to base and but little swollen; no trace of a tympanic hood. 



Dioptidae. 



34. Subcosta strongly sinuous and much swollen at base; a lateral hood at base 



of abdomen A few Geometridae (p. 41) 



35. Sc and R of hind wing fused for a very short distance, then sharply divergent, 



separate from base, or connected by a weak cross vein (figs. 413-422) ; 

 tympanic hood absent 36 



