THE TITYRUS SKIPPER. 311 



so great that it cannot be captured without danger of its 

 being greatly defaced in its struggles to escape. The females 

 lay their eggs, singly, on the leaves of the common locust- 

 tree {Robinia pseudacacia), and on those of the vis&d locust 

 (Robinia viscosci), which is much cultivated here as an 

 ornamental tree. The caterpillars are hatched in July, and 

 when quite small conceal themselves under a fold of the 

 edge of a leaf, which is bent over their bodies and secured by 

 means of silken threads. When they become larger they 

 attach two or more leaves together, so as to form a kind of 

 cocoon or leafy case to shelter them from the weather, and 

 to screen them from the prying eyes of birds. The full- 

 grown caterpillar (Fig. 133), which Fig. 133. 

 attains to the length of about two 

 inches, is of a pale green color, trans- 

 versely streaked with darker green, 

 with a red neck, a very large head roughened with minute 

 tubercles, slightly indented or furrowed above, and of a dull 

 red color, with a large yellow spot on each side of the 

 mouth. Although there may be and often are many of these 

 caterpillars on the same tree and branch, yet they all live 

 separately within their own cases. One end of the leafy 

 case is left open, and from this the insect comes forth to feed. 

 They eat only, or mostly, in the night, and keep themselves 

 closely concealed by day. These caterpillars are very clean- 

 ly in their habits, and make no dirt in their habitations, but 

 throw it out with a sudden jerk, 

 so that it shall fall at a consider- 

 able distance. They frequently 

 transform to chrysalids within the 

 same leaves which have served 

 them for a habitation, but more 

 often quit the trees and construct 

 in some secure place a cocoon 

 (Fig. 134) of leaves or fragments 

 of stubble, the interior of which is lined with a loose web 



