THE LARCH LAPPET: J)ESCKIPT10X OF THE MOTH. 



97 



Fig. 23. — FfiiiiUe 

 Larch lappet-moth. 



th e 



toothed or scalloped. When at rest they are pressed against the sides 

 of tlie abdomen, in the form of a steep roof, the outer edges of the hind 

 wing.s protruding more or less from under the outer edge of the fore 

 ones. The legs [which are stretched forward at rest] are heavily 

 clothed exteriorly with tufts of long, snowy-white hairs, the forward 

 shanks having a tuft of blackisii ones on tlieir insides at their base. 

 The female, shown in Fig. 23, is quite unlike the male, being much 

 larger and differently colored. It has a pe- 

 culiarly dehcate or mellow appearance, from 

 the softness of its colors and the thinness and 

 translucency of its wings. The latter, when 

 extended, measure an inch and a half or 

 slightly less. Their hind edge is occupied by 

 a slender white band or line. Forward of this 

 IS a narrow, pale, dusky band which is 

 abruptly widened near its middle to double 

 its usual breadth, this widened part occupying 

 two of the interstices between the veins. This band is margined on 

 its anterior side by a white line, by which it is separated from a much 

 broader and more dusky band, which is waved in its middle in con- 

 formity with the dilation in the narrow band behind it. Forward of 

 this the wings are milk-white, crossed by four very faint, cqui-distant, 

 wavy bands of the same delicate, pale, dusky hue Avith those behind, 

 these bands being often obsolete on the middle of the wing and dis- 

 tinct at their ends only. The veins are prominent and white, form- 

 ing slender lines of this color crossing all the bands. The hind wings 

 are of the same soft, dusky tint as the bands on the fore-wings, but 

 more pale; on their hind margin is a white line or slender band. The 

 hind edge of both pairs of wings is perfectly entire as in the male, and 

 their fringe is pale dusky on the fore-wings, crossed with white 

 lines at the tips of the veins. The body is clothed with incumbent 

 milk-white hairs, the tip of the abdomen having a pale brown tuft, and 

 the crest on the base of the thorax appears like a large, elevated, black- 

 ish spot. The antennae in this sex are very slightly crooked in their 

 middles, and their branches, though equally thick with those of the 

 males, are much shorter, being about four times as long as the diame- 

 ter of their stalk. These branches are longest in the middle, and are 

 gradually shorter from thence, both toward the base and the tips." 



Sexual Difference in the Larval Meltings. 

 It has been my habit to preserve all the head-cases cast off at the 

 several meltings of the lepidopterous larva? reared by me from the egg, 

 to serve as a tangible record of the number of molts undergone, and 

 for the further reason that they usually present interesting specific 

 features which render them valuable for illustration, and for preserva- 

 tion in a biological collection. In collecting the head-cases of the abo\-e 

 brood of T. laricis, I was at a loss to account for the great deficiency 

 in number of those of the fourth molt. There were fifteen less than 

 in the preceding molt. When the moths had all emerged — equal in 

 13 



