LEPIDOPTERA 253 



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 very thin, containing but little silk. 



The promethea-moth, Callosamia promethea. — This is the most 



Fig. 444. — Callosamia promethea, female. 



common of the giant silk- worms. The wings of the female (Fig. 444) 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 2 inches 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 seg- 

 ment. This larva feeds on the leaves of a large proportion of our com- 

 mon fruit and forest- trees; but we have found it more frequently on 

 wild cherry, lilac, tulip-tree, ash, and sassafras 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. 445) 

 is interesting in structure. It is greatly elongated and is enclosed in a 

 leaf, the petiole of which is securely fastened to the branch by a band of 

 silk extending from the cocoon; thus the leaf and enclosed cocoon hang 

 upon the tree throughout the winter. At the upper end of the cocoon 

 there is a conical valve-like arrangement which allows the adult to emerge 

 without the necessity of making a hole through the cocoon. This structure 

 is characteristic of the cocoons of the moths of this and the following genus. 



