LEPIDOPTERA 



725 



grown about 75 mm. in length. It is pale bluish green with a pearl- 

 colored head. It has a pale yellow stripe along each side of the body, 

 and a transverse yellow line on the back between each two abdominal 

 segments. The cocoon resembles that of the preceding species in form, 

 but is ver>^ thin, containing but little silk. 



The Promethea-moth, Callosdmia promethea. — This is the most 

 common of the giant silk-worms. The wings of the female (Fig. 927) 

 are light reddish brown; the transverse line crossing the middle of 

 the wings is whitish, bordered within with black; the outer margin of 

 the wings is clay-colored, and each wing bears an angular discal spot. 

 The discal spots vary in size and distinctness in different specimens. 

 The male differs so greatly from the 

 female that it is liable to be mistaken 

 for a distinct species. It is blackish, 

 with the transverse lines very faint, 

 and with the discal spots wanting or 

 very faintly indicated. The fore wings 

 also differ markedly in shape from 

 those of the female, the apex being 

 much more distinctly sickle shaped. 

 The males fly by day . The larva when 

 full grown measures 50 mm. or more 

 in length. It is of a clear pale bluish- 

 green color; the legs and anal shield 

 are yellowish ; and the body is armed 

 with longitudinal rows of tubercles. 

 The tubercles are black, polished, 

 wart-like ~ elevations, excepting two 

 each on the second and third thoracic 

 segments, which are larger and rich 

 coral-red, and one similar in size to 

 these but of a yellow color on the 

 eighth abdominal segment. This lar- 

 va feeds on the leaves of a large pro- 

 portion of our common fruit and forest 

 trees ; but we have found it more fre- 

 quently on wild cherry, lilac, tulip- 

 tree, and ash than on others. The co- 

 coons can be easily collected during 

 the winter from these trees. This is 

 the best way to obtain fresh specimens 

 of the moths, which will emerge from 

 the cocoons in the spring or early 

 summer. The cocoon (Fig. 928) is 

 interesting in structure. It is greatly pjg g28.—Callosamia promethea, 

 elongated and is enclosed in a leaf, cocoon, 

 the petiole of which is securel}* fas- 

 tened to the branch by a band of silk extending from the cocoon; 

 thus the leaf and enclosed cocoon hang upon the tree throughout the 



