108 ILLINOIS BIOLOGICAL MONOGRAPHS [108 



Genera of Notodontinse : 



a. First abdominal segment bearing a higher dorsal gibbosity than sec- 

 ond, gibbosity usually either bifurcate or bearing a pair of eor- 

 nicula. 

 b. Dorsal cornieulum of segment 8 single, that of segment 1 obscurely 

 bifurcate. Ianassa 



bb. Dorsal cornieulum of segments 1 and 8 distinctly bifurcate, 

 c. Segments 4 and 5 not gibbous above; color between humps on 

 segments 1 and 8 mainly in a single elliptical patch ; labrum 

 notched to two-thirds its depth. Hyparpax 



cc. Segments 4 and 5 usually gibbous above ; color between seg- 

 ments 1 and 8 never in a distinct elliptical patch ; labrum not 

 notched to two-thirds its depth. Schizura 



aa. First abdominal segment not bearing a higher dorsal gibbosity than 

 second ; gibbosity, when present, neither bifurcate nor bearing a 

 pair of cornicula. 

 b. Segment 8 bearing a distinct dorsal hump or horn or pair of cor- 

 nicula. 

 c. Dorsal processes of segment 8 slender, horn-like. 



d. Horn single, similar to the caudal horn of a sphingid. 



Pheosia 

 dd. Horns paired, slender and sharply pointed. Ptilodon 



cc. Dorsal hump of segment 8 broad, not horn-like. 

 d. Segment 2 conspicuously gibbous above. 



e. Abdomen bearing high dorsal gibbosities on eight segments. 



Nericc 

 ee. Abdomen bearing dorsal humps on not more than five seg- 

 ments. (In part) Hypcracschra 

 dd. Segment 2 not gibbous above. 



e. Segment 8 swollen and discolored over entire dorsal half; 

 coloration mainly a series of longitudinal stripes. 



Symmerista 

 ee. Segment 8 not swollen over entire dorsal half. 



f . Anal prolegs short and rounded ; coloration in indefinite 

 transverse stripes. Odontosia 



ff. Anal prolegs usually elongate. 



g. Head bearing a pair of dark dorsal spots. Ellida 



gg. Head unicolorous. 



h. Coloration principally a series of conspicuous lon- 

 gitudinal stripes on dorsal half of each segment 

 and rounded spots at base of each leg. Dasylophia 

 hh. Coloration principally a series of conspicuous trans- 



