48 SOME INSECTS INJtJEIOUS TO FORESTS. 



last 2 segments are free from granules. On the anterior half of the 

 side of each abdominal segment except the last, a spiracle (fig. 16, c) 

 similar to that on the mesothorax, except that it is much smaller, is 

 to be found. In mature larvae each abdominal segment bears a longi- 

 tudinal fold on each side, known as the pleural fold. On immature 

 larv^ the pleural folds on the first 2 abdominal segments are so 

 obscure as to be scarcely noticeable. The anal fold is quite hairy and 

 bears the anal opening. Numerous hairs occur upon each segment of 

 the entire body. 



p^tpa.— The pupa (fig. 17) shows the form in some degree of both the 

 larva and the adult. The number of segments is the same as in the 

 larva; the first abdominal segment, however, is not visible upon the 

 under side of the body. The head is of the same general shape as that 

 of the adult, but is bent forward and under, so that the mouth-parts 

 point directly back toward the posterior end of 

 the body. Several bristles are found upon the 

 anterior part of the head. The antennae are well 

 developed and are coiled on the under side, of the 

 elytra, or wing covers, which extend from the 

 mesothorax in a posterior lateral direction, the tips 

 being directly underneath the body and attain- 

 ing the fourth abdominal segment. The elytra 

 thus lie between the body and the first two pairs 

 of legs. The third pair of legs is between the body 

 and the elytra. The wings are flattened against 

 the under side of the elytra, each one projecting 

 slightly beyond the outer side rnargin of the ely- 

 tron, under which it lies. The elytra are attached 

 to the mesothorax and the wings to the meta- 



FiG. 17.— The pine sawyer: tliorax. 



Pupa. About twice nat- There is a large fleshy tubercle at each side of 

 the prothorax. The legs are folded underneath 

 the body. The first pair is borne by the prothorax, the second by 

 the mesothorax, and the third by the metathorax. The mesothorax 

 bears a spiracle in the same position as that of the larva, and the first 5 

 abdominal segments bear spiracles; the rest apparently do not. Upon 

 the dorsal surface all segments of the thorax and abdomen bear bristles. 

 The ventral surface of all abdominal segments, except the last, is smooth. 

 The last abdominal segment, which occupies the extreme posterior end 

 of the body, has a peculiar triangular shape. One of the points of the 

 triangle is prolonged upward into a sharp, chitinized spine. The two 

 lower points of the triangle are armed with several chitinized bristles. 

 The anal segment occurs directly beneath the last abdominal segment, 

 and is inclosed on three sides by the latter. A strongly marked sexual 

 difference is to be found between the anal segment of the male and that 



