LEPIDOPTERA 



727 



Mountain region and in Arizona; and Samia rubra in the Pacific 

 States. In Samia rubra the crescent-shaped white spot near the 

 center of the hind wings is more elongate and pointed than in the 

 other species. 



The Ailanthus-worm, Philosdmia Walkeri. — This is an Asiatic 

 species which has been introduced into this country. It has become 



Fig. 930. — Samia cecropia, cocoon. 



a pest in the vicinity of New York City, where it infests the Ailanthus 

 shade trees. The moth differs from all our native species of this 

 family in having rows of tufts of white hairs on the abdomen. Its 

 cocoon resembles that of the Promethea-moth. The specific identity 

 of this species is in doubt. 



Family BOMBYCID.^ 



The Silk-Worm 



The family Bombycidas is not represented in our fauna; but a 

 single species, the silk-worm, is frequently bred in this country, and 

 is usually present in collections of Lepidoptera. 



The silk-worm, Bombyx niori. — The moth (Fig. 931) is of a cream- 

 color with two or three more or 

 less distinct brownish lines across 

 the fore wings and sometimes a 

 faint double bar at the end of 

 the discal cell. The head is small ; 

 the antennse are pectinated 

 broadly in both sexes; and the 

 ocelli, palpi, and maxillas are 

 wanting. A striking feature of 

 the venation of the wings (Fig. 

 932) is the obvious presence of 

 the base of vein Ri in the hind 

 wings. 



The usual food of the silk- 

 worms is the leaf of the mulberry. Our native species, however, are 

 not suitable. The species that are most used are the white mulberry 



Bombyx mori. 



