1910] A Structural Study of Some Caterpillars 103 



11. Seta iii of labrum as near to ii as to iv, far from margin Pieridae 



11. Seta iii of labrum on margin Nymphalidae 



12. Hooks of prolegs in an angulated band, shortest at the angle; with addi- 



tional prolegs (two pair) without hooks Megalopygidae. 



12. Hooks of prolegs in a straight or curved band; no additional prolegs. . .13 



13. Anal prolegs reduced or modified, with fewer or no hooks. . Notodontidae 



13. Anal prolegs larger than ventral ones 14 



14. With dense fine secondary hair on head, body with tufted hair 15 



14. With some sparse secondary hair on head, body with tufted hair. . Arctiidae 



14. Without secondarv hair on head, body often without secondary or tufted 



hair " ". 17 



15. Eversible dorsal glands on posterior abdominal segments; a tuft of second- 



ary hair on the adfrontals; five warts on mesothorax Liparidae 



15. No eversible dorsal glands; no such tuft of secondary hair IG 



IG. Three warts on mesothorax, the upper very large Syntomidae 



16. Four nearly equal warts on mesothorax Noctuidae (Pantheinae) 



17. Body with primary hair only Noctuidae 



17. Body with tufted or secondarv hair IS 



18. Fourteen legs (first prolegs wanting ) Nolidae 



18. Sixteen legs 19 



19. Two warts above spiracle on each segment of abdomen 



Zygaenidae (Pyromorphidae) 



19. Three warts above spiracle on each segment of abdomen, or with second- 



ary hair 20 



20. Adfrontal puncture three times as far from lower as from upper seta. . 



Arctiidae 



20. Adfrontal puncture not more than twice as far from lower as from upper 



seta Noctuidae (Acronyctinae) 



21. Without secondary hair 22 



21. With dense fine secondary hair (often minute) 23 



Anal legs wanting; a series of small outer hooks on prolegs. . Drepanidae 



Anal legs reduced; a few outer hooks on prolegs Thyatiridae 



Anal legs large; ventral prolegs reduced or wanting; no outer hooks on 

 prolegs Geometridae 



23. Secondary hair on antennae, palpi, and sclerites a, b and c of labium 



Lasiocampidae 



23. No secondary hair on antennae, palpi, or tip of labium 24 



24. Seta vi of labrum distant from margin, migrated toward ii* 25 



24. Seta vi of labrum marginal or nearly so 26 



25. Hair microscopic; without tufted hair Sphingidae 



25. Hair conspicuous; with tufted as well as secondary hair. . . . Apatelodesf 



26. An unpaired dorsal spine or tubercle on ninth abdominal segment 



Citheroniidae 



26. Usually with an unpaired dorsal spine on eighth abdominal segment, 



but never with one on the ninth Saturniidae 



* This separation does not entirely hold, see the descriptions of the individual families. 

 t Probably does not belong to the Notodontidae. 



22 

 22 



