INSECTS INJURIOUS TO CLOTHES 193 



larva begins, at once, to make a case for itself. The case 

 is a nearly cylindrical tube open at both ends. It is, how- 

 ever, slightly larger in the middle, thus resembling a cigar 

 in shape (Fig. 53). The tube is made of silk and frag- 

 ments of the material upon which the larva is feeding. 

 When feeding, the larva thrusts out its head together with 

 its thorax, which bears the three pairs of legs ; and holding 

 fast to its case with a pair of claspers on the posterior end 

 of the body drags its house along with it wherever it goes. 

 When disturbed, the larva retreats 

 quickly within its case. The larvae 

 feed on woolens, clothing, carpets, 

 furs, and feathers, and are exceedingly fig. 53. — Case of the 

 destructive. Fernald says that these case-making clothes 

 moths "breed during the summer, 

 but not in winter, even when kept in a room warmed 

 by a furnace where the heat was uniform day and night. 

 The moths emerge in June and July, and some even as 

 late as August, yet there is but a single generation 

 annually, so far as I have observed." In the South 

 there are probably more generations a year. 



The young larva, of course, soon finds its case too small 

 and, as it grows, it has to enlarge the case from time to 

 time. This enlargement is done in a very interesting man- 

 ner. Without emerging from its case, the larva cuts a 

 slit halfway down one side, thus forming a triangular 

 opening. Into this opening it inserts a triangular gore of 

 the woolen material upon which it is feeding. This process 

 is repeated on the opposite side of the case and without 

 leaving its retreat it turns around and repeats the same 

 thing on the other half of the case. Thus the case is 

 enlarged in diameter, but it remains for the larva to 

 o 



