FAMILY BRUSH-FOOTED BUTTERFLIES. 91 



nearly uniform black-gray through a mingling of crowded trans- 

 verse threads of black and blue (as seen under a lens), the broad 

 outer margin ashen white, much flecked with brown. Expanse 

 3-3^ inches. 



Caterpillar. — Head black, not spined on summits. Body 

 spinous, the spines much longer than the segments, but no me- 

 diodorsal spines on either first or second abdominal segments; 

 velvety black, sprinkled with white papillae and with a row of 

 large mediodorsal orange spots; prolegs reddish. Length 2 

 inches. 



Chrysalis. — Dark yellow-browni marked with blackish fuscous, 

 often with a pale bloom and tinged with roseate ; larger tubercles 

 red-tipped ; ocellar tubercles pointed; no mediodorsal tubercle 

 on second abdominal segment. Length 1 inch or more. 



The eggs are barrel-shaped, slightly higher than broad, 

 with seven or eight thin high vertical ribs fading next base 

 and ure of a pale yellow at first, changing to dark brown 

 and then to inky black; they are laid in a single layer in 

 rings encircling or nearly encircling one of the terminal 

 twigs of the food-plant near its tip and hatch in from nine 

 to sixteen days. The caterpillars feed principally npon 

 willows and elm, but also on poplars and to a less extent on 

 a number of allied plants; they are gregarious throughout 

 life, and in feeding at first range themselves side by side in 

 compact columns; they spin, however but little web and 

 this merely to make a track upon the stems of the food- 

 plant, along which they travel in a procession Avhen moving 

 from place to place. The chrysalis state lasts from eight 

 to sixteen days according to the season, and the butterfly is 

 double-bfooded, hibernating in the perfect stage. The 

 butterflies come out the first of the butterfly hibernators — 

 any ,varm winter day may lure them — and lay eggs early in 

 May, from w^hich a first brood of the season's butterflies 

 springs into being very late in June or early in July; by 

 the middle or last of July eggs are again laid, and the sec- 

 ond brood of butterflies is on the wing early in September 



