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edges, and forming an oblong ovate cavity, thinly lined with 

 brownish silk ; there is also a circular opening at each end just 

 large enough for the caterpillar to crawl out. The caterpillar 

 has a black, very roughly punctured head, furnished on each 

 side, just behind the five ocelli, with two flexible, slender, spat- 

 ulate antennae (?) which, however, seem to be without joints 

 and incapable of motion. Are they not intended as com- 

 passes to measure the interior of its habitation ? It has also 

 four palpi, two very minute, and not ordinarily visible ; the 

 other two much longer, attached to the maxillse, and apparently 

 three-jointed. These palpi are moved with the utmost rapidity 

 during the whole time that the insect's head is thrust forth 

 from its cocoon. The first segment is black and corneous, the 

 next, and the rest of the body, are reddish-brown, and finely 

 granulated. The spiracles, though small, are very distinct and 

 of a black color. The first six legs are corneous and conical, 

 and about equal in size. The prolegs of the usual number 

 (probably, for I could not see the terminal pair), are very short, 

 retractile (?) with only the oval coronet of hooks visible. The 

 hindmost extremity is obliquely truncated, as in Scolylus, the 

 truncated portion circular, and forming a flat plate of a drab 

 color, which exactly closes the hinder orifice of the cocoon 

 when the insect is included within it. The caterpillar and 

 its case were found on the oak, the leaves of which it eats. 

 It eats mostly by night, when it wishes to be stationary; to 

 change its place it comes partly out and cuts the threads, 

 and then stretching further out, lays hold of the leaf with 

 its six fore legs, and suddenly shortening its body, brings up 

 the cocoon with a jerk. In this way it goes along half an 

 inch at a time. Internally the case is large enough to permit 

 the caterpillar to turn around, so that it can come out at either 

 end at pleasure, and if disturbed at the hinder end, it turns 

 with great facility, and shows its head and jaws to the disturber. 

 All my attempts to make the insect leave its case entirely 

 have been in vain, for it clings by its hind prolegs to the inte- 



