253] THE LARVAE OP TEE COCCI NELLI DAE— GAGE 21 



ABDOMEN 



The abdomen of all coccinellid larvae is composed of ten segments 

 which are connected by more or less distinct coria. This coria is usually- 

 more prominent on the ventral than on the dorsal aspect. The abdomen 

 is generally subdepressed, widest on its cephalic half, and tapering on its 

 caudal half. The abdomen in C. bivulnerus narrows gradually toward the 

 caudal end. The first three segments are about as wide as the metathorax. 

 This is also true of Epilachna and of all of the genera of Coccinellini in 

 which the first, second, third, and fourth abdominal segments are subequal 

 in width. The remaining abdominal segments become narrower toward 

 the caudal end. In Microweisea and Scymnus the first, second, and third 

 abdominal segments are the widest; caudad of the third the abdomen 

 becomes narrower. In Hyperaspis the first, second, fifth, and sixth seg- 

 ments are subequal in width; while the third and fourth are the widest 

 segments in the body. 



In C. bivulnerus the first abdominal segment is slightly narrower and 

 shorter than the metathorax. Its tergum (Figs. 1, 2) bears four distinct 

 senti arranged in a transverse row. The dorsal senti are adjacent on the 

 dorso-meson and the dorso-lateral ones are placed on each side near the 

 lateral margin of the tergum. There is a small circular pinaculum at the 

 base of each sentus. The dorsal pinacula are brown or yellow colored and 

 the dorso-lateral ones are white. There is also a few inconspicuous setae 

 on the surface of each pinaculum. The lateral aspect is a vertical area, 

 almost square, and bears the large lateral sentus, at the base of which there 

 is a very large pinaculum nearly covering the entire surface. The para- 

 lateral group is wanting. The sternum (Fig. 3, st) is about as long as the 

 tergum. The coria between it and the metatergum is not at all distinct. 

 The cuticle is thin and membraneous and bears two groups of small ventral 

 setae adjacent to the ventro-meson. The ventro-lateral setae are wanting. 



The external structure of segments two to five inclusive is similar, 

 however, each succeeding segment is narrower than the preceding one. 

 The coriae between the segments are distinct. Each tergum has four 

 senti arranged in a transverse row. The dorsal senti and their pinacula 

 are adjacent to the dorso-meson; the dorso-lateral senti are located in a 

 position similar to those of the first abdominal segment. All of the pina- 

 cula are dark brown in color and bear numerous fine setae. Each lateral 

 aspect is almost square and bears a distinct lateral sentus. The pinacula 

 at the base of these senti are small. In the second and third segments 

 ventrad of the lateral senti there is a solitary small seta; while in segments 

 four and five there is a prominent chalaza surrounded by a group of small 

 setae. This group represents the paralaterals. Each sternum is as long 

 as its respective tergum and the coriae between the sterna are distinct. 

 The cuticle is thin and membraneous and bears on each sternum four groups 



