162 TEE COMMONER BUTTERFLIES. 



through August. The eggs are shaped as in the other 

 species, with about sixteen vertical ribs, highest above, and 

 are pea-green, changing after two days to a salmon-red; 

 they are laid singly on the stems and perhaps also on the 

 leaves of the food-plant and hatch in eight or nine days. 

 The caterpillar feeds principally ujion oaks, but also upon 

 some Leguminous plants, and makes a nest like the pre- 

 ceding species, but always, even when young, travels to a 

 distance for its food. AVhen winter approaches, the hiber- 

 nating caterpillar takes on a vinous tint. In the spring 

 the chrysalis state lasts a full month. 



THANAOS BRIZO— THE SLEEPY DUSKY- WING 



(Nisoniades brizo.) 



Butterfly. — Upper surface of wings very dark grayish brown, 

 the fore wings flecked with white scales especially toward the 

 apex, with no vitreous spots, but crossed by two distant dark 

 bands with jagged black edges, the outer band the more distinct; 

 hind wings with a few small obscure pallid spots on outer half. 

 Under surface dark fuliginous brown, the fore wings gray 

 apically and both with a marginal and premarginal series of small 

 whitish spots. Expanse somewhat more than \^ inches. 



Caterpillar. — Head dark brown, paler above, with an orange 

 spot at base of mandibles. Body naked, briefly pilose, pale green 

 with an indistinct paler lateral stripe and dotted with darker 

 green. Length more than 1 inch. 



Chrysalis. — Green, the appendages infuscated, the rest as in 

 the other species. Length ^ inch. 



Occurs in every part of our district in moist shady spots 

 and forest openings, flying swiftly about three feet from 

 the ground with sudden lateral movements. It hibernates 

 as a full-grown caterpillar and is single-brooded, appearing 

 on the wing very early in May, becoming abundant by the 

 tenth of the month and flying until the middle of July. 

 The eggs, shaped as in the other species, have fifteen ribs 

 of uniform height. The caterpillar feeds upon scrub oak 



