OO MAINE AGRICULTURAL EXPERIMENT STATION. I902. 



which have to do with the movements of the ovipositor. These 

 muscles are eight in number, four on either side of the median 

 line. They are attached at their ventral ends to the ovipositor, 

 and run dorsally and somewhat laterally around the intestine to 

 be attached to the dorsal wall of the abdomen. When these 

 muscles are contracted they bring the ovipositor out from its 

 position in the groove on the seventh and eighth abdominal som- 

 ites, where it lies when not in use, to the position in which it is 

 used in depositing eggs. In this position it is placed at an angle 

 of about thirty degrees with the abdomen. 



In the thorax the segmental arrangement of the muscles is 

 greatly modified. On the dorsal side there are two rows of 

 longitudinal muscles like those of the abdomen. On the median 

 dorsal line of the mesothorax four muscles are attached. One 

 pair of these muscles runs anteriorly and laterally and is attached 

 to the ventral wall of the prothorax just posterior to the anterior 

 legs. The other pair passes posteriorly and laterally and is 

 attached just posterior to the hind legs. The arrangement of 

 these muscles is such that when they are viewed from the dorsal 

 side they form a cross the four extremities of which are attached 

 to the ventral surface. 



Attached to the fold of the integument that lies between the 

 abdomen and metathorax, with their posterior ends overlapping 

 the ventral ends of the posterior pair just mentioned, is another 

 pair of muscles. These converge as they run forward, and are 

 attached to a prominence on the floor of the metathorax near its 

 anterior end. Between the posterior ends of these two sets of 

 muscles another pair of muscles is attached. These diverge as 

 they run forward, and are attached at the bases of the third pair 

 of legs. From this point they converge and at the anterior end 

 of the somite they are attached to the fold of integument between 

 the meta- and mesothorax. Another pair of muscles is attached 

 to the floor of the metathorax ; they diverge as they run forward 

 and are attached at the bases of the legs in the mesothorax. 

 From this point they converge and are attached together on the 

 floor of the posterior part of the prothorax. 



In the prothorax there is a pair of muscles that has the same 

 arrangement as the muscles last described, being attached at 

 their posterior ends to the fold of integument between the pro- 

 and meso-thorax and running forward to the head. These also 



