372 LEPIDOPTERA. 



or the camp * lackey-caterpillars of Europe, for which they 

 have been mistaken. From the first to the middle of June 

 they begin to leave the trees upon which they have hitherto 

 lived in company, separate from each other, wander about 

 awhile, and finally get into some crevice or other place of 

 shelter, and make their cocoons (Plate VII. Fig. 15). 

 These are of a regular long oval form, composed of a tliin 

 and very loosely woven web of sUk, the meshes of which 

 are filled with a thin paste, that on drying is changed to a 

 yellow powder, like flour of sulphur in appearance. Some 

 of the caterpillars, either from weakness or some other 

 cause, do not leave their nests with the rest of the swarm, 

 but make their cocoons there, and when the webs are opened 

 these cocoons may be seen intermixed with a mass of 

 blackish grains, like gunpowder, excreted by the caterpillars 

 during their stay. From fourteen to seventeen days after 

 the insect has made its cocoon and changed to a chrysalis, 

 it bursts its chrysalis-skin, forces its way through the wet 

 and softened end of its cocoon, and appears in the winged 

 or miller form. Many of them, however, are unable to fin- 

 ish their transformations by reason of weakness, especially 

 those remaining in the webs. Most of these will be found 

 to have been preyed upon by little maggots living upon the 

 fat within their bodies, and finally changing to small four- 

 winged ichneumon wasps, which in due time pierce a hole 

 in the cocoons of their victims, and escape into the air. 



The moth (Plate VIL Fig. 14 male. Fig. 17 female) 

 of our American lackey-caterpillar is of a rusty or reddish- 

 brown color, more or less mingled with gray on the middle 

 and base of the fore wings, which, besides, are crossed by 



are blue, with a narrow red stripe; on the top of the eleventh ring is a little 

 blackish wart; and the belly is dusky. 



* The casirensis, or camp-caterpillar, has a naiTow broken white line on the 

 top of the back, separating two broad red stripes, which are dotted with black; 

 the sides are blue, with two or three nan-ow red stripes ; the head and first ring 

 are not marked with black dots; there is no wart on the top of the eleventh ring; 

 and the belly is white, marbled with black. 



