288 INSECTS INJURIOUS TO VEGETATION. 



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. These are of 

 a regular long oval form, composed of a thin and very loosely 

 woven web of silk, 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 inter- 

 mixed with a mass of blackish grains, like gunpowder, excreted 

 by the caterpillars during their stay. From fourteen to seven- 

 teen 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 

 finish 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 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 two oblique, straight, dirty white lines. It expands from 

 one inch and a quarter to one inch and a half, or a little more. 

 This moth* closely resembles the castrensis, and still more the 



the sides are blue, with two or three narrow red stripes ; the liead and first ring 

 are not n^arked with black dots; there is no wart on the top of the eleventh 

 ring ; and the belly is white, marbled with black. 



* A short but very accurate account of this insect may be found in the late 

 Professor Peck's " Natural History of the Canker Worm," printed at Boston, 

 among the papers of the " Massachusetts Society for promoting Agriculture," 

 in the year 1796. Professor Peck seems to have been aware that it was not 

 identical with the Neiistria, but he forcborc to give it another scientific name. 



