3 6 ° 



REPORT OF THE COMMISSIONERS OF 



Joutel, to the larva gnawing particles from the bark to attach to its tiny case. The 

 full grown larva removed from its protecting bag is shown at figure 16 and the 

 creature's method of carrying its apparently cumbersome retreat is represented at 

 figure iy. The pupal cases of the two sexes are shown at figures 18 and 21 and the 

 wide difference between the adult insects at figures 19 and 20. The female is almost 

 legless, wingless and nearly helpless, while the male is a small black moth with well 

 developed wings and beautiful feathery antennae. 



Life history. The eggs survive the winter within the larval and pupal cases of 

 the female. The young appear sometime in May or early in June and begin by 

 eating the softer portions of the leaf. They repair to the stems when not feeding 

 and here it is that they sometimes cover their interesting shelters by biting off 

 pieces of the bark and attaching them to the case. This habit was brought to my 



a b o d e 



Fig. 3 — Young caterpillar making its case on a leaf: a, position as it begins operations; i, beginning 

 the case; c, caterpillar under strip and upside down; d, caterpillar after turning; e, case more 

 enlarged; /, case complete. (After Riley, Bull. 10 U. S. Dept. Agr., Div. Ent.) 



notice by Mr Joutel who, in the course of his studies of the insect, found many tiny 

 brown cases on the older bark, green ones on the younger bark and occasionally 

 party colored ones. The gnawed condition of the bark showed where the color had 

 been obtained. This is not the first record of this interesting habit for the same 

 thing was observed by Mr S. S. Rathvon in 1867. He also mentions an instance of 

 the young larvae of this insect hatching in his office and in the absence of food 

 escaping to the floor where they proceeded to attach to their cases pieces of paper, 

 leather, straw matting and even scales of lime, in fact taking anything at hand. 

 The cases may also be constructed on the leaves. Dr Riley's exceedingly graphic 

 account of this operation is as follows : " The way in which this bag is prepared is 

 curious (Fig. 3). The young larva crawls on a leaf and, gnawing little bits from the 

 surface, fastens these together with fine silk spun from its mouth. Continually 

 adding to the mass, the larva finally produces a narrow, elongated band, which is 

 then fastened at both ends onto the surface of the leaf by silky threads. Having 

 secured itself from falling down by some threads, it now straddles this band and, 



