THE WHITE-MARKED ORGYIA. 367 



apple-trees are much infested by them, as was the case in 

 the summer of 1828. In the summers of 1848, 1849, and 

 1850, they were very numerous on trees in Boston, both in 

 private yards and on the common, where the horse-chestnuts, 

 which seem ordinarily to escape the attacks of insects, were 

 almost entirely stripped of their leaves by these insects. 

 When they have done eating, they spin their cocoons on the 

 leaves, or on the branches or trunks of the trees, or on fences 

 in the vicinity. The chrysalis is not only beset with little 

 hairs or down, but has three oval clusters of branny scales 

 on the back. In about eleven days after the change to the 

 chrysalis is effected, the last transformation follows, and the 

 insects come forth in the adult state, the females wingless, 

 and the males with large ashen-gray wings, crossed by wavy 

 darker bands on the upper pair, on which, moreover, is a 

 small black spot near the tip, and a minute white crescent 

 near the outer hind angle. The body of the male is small 

 and slender, with a row of little tufts along the back, and 

 the wings expand one inch and three eighths. The females 

 (Plate VII. Figs. 2 and 3) are of a lighter gray color than 

 the males, their bodies are very thick, and of an oblong oval 

 shape, and, though seemingly wingless, upon close examina- 

 tion two little scales, or stinted winglets, can be discovered 

 on each shoulder. These females lay their eggs upon the 

 top of their cocoons (Plate VII. Fig. 5), and cover them 

 with a large quantity of frothy matter, which on drying 

 becomes white and brittle. Different broods of these insects 

 appear at various times in the course of the summer, but 

 the greater number come to maturity and lay their eggs in 

 the latter part of August and the beginning of September, 

 and these eggs are not hatched till the following summer. 

 The name of this moth is Orgyia * leucostigma (Plate VII. 



* This name is derived from a word which signifies to stretch out the hands. 

 and it is applied to this kind of moth on account of its resting with the fore legs 

 extended. The Germans call these moths streckfilssige Spinner ; the French, ^a/Vo* 

 ctendues; and the English, vaporer-moths; the latter probably because the males 

 are seen flying about ostentatiously, or vaporing, by day, when most other moths 

 keep concealed. 



