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 (j Robinia pseudacaeia), and on those of the viscid locust 
( llobinia viscosa ), which is much cultivated here as an 
ornamental tree. The caterpillars are hatched in July, and 
when (piite 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 then* 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 
