FAMILY BRUSH-FOOTED BUTTERFLIES. 99 



few black-bordered orange spots at the base, and a premarginal 

 series of plain orange spots, besides a double series of crenulate 

 blue lines, next outer margin. Expanse nearly 3 inches. 



Caterpillar. — Head dark drab, tuberculate, the summits 

 crovvjied with a large tubercle, rounded at tip but with raised 

 points ; the principal tubercle behind it tumid, but little higher 

 than broad. Body naked, humped, and irregularly tuberculate, 

 of various shades of green, especially olive, with a dorsal patch 

 of pal 3 butf; a pair of long, clubbed, prickly tubercles on second 

 thoracic segment; not more than about twenty minute smooth 

 warts on any one segment above the spiracles. Length nearly \\ 

 inches. 



Chrysalis. — Varying from creamy white to silvery gray, the 

 wings margined with greenish brown, the body grotesquely 

 streaked; basal wing-tubercle produced to a minute, backward- 

 directed point; tail-piece, seen from above, less than twice as 

 long as its width at apex. Length nearly 1 inch. 



The eggs, which are globular, pitted, studded with short 

 filaments, and grayish green, are laid singly on the upper 

 surface of the extreme ti^^s of the pointed leaves of the 

 food-plant, leaves on young plants, only a few feet above 

 the ground, being usually selected; they hatch in from 

 seven to nine days. The caterpillars usually feed upon 

 black and yellow birch, preferably the former, willow and 

 poplar, but have also been found on shadbush and some 

 other plants. As soon as it has hatched the young cater- 

 pillar devours its ^gg, and then begins to feed upon the 

 leaf upon which it was born, beginning at the extreme 

 tip, but always leaving the midrib untouched as it proceeds 

 toward the base; when resting after a meal, it always 

 takes its station on the stripped midrib, to which it fastens 

 with much silk minute bits of leaf to strengthen it; and 

 like all the other species of the genus it makes while 

 young a loose ball of the size of a small pea out of bitten 

 scraps of leaf held together by a few strands of silk and 

 hangs it by a thread or two to the stripped midrib, so that 

 it is moved by every breath of wind — a device, perhaps, to 



