249] THE LARVAE OF THE COCCI NELLI DAE— GAGE 17 



ligula is the distal portion of the labium. In C. bivulnerus it is composed 

 of the fused stipulae, glossae, and paraglossae. Near the ventro-lateral 

 margin there is a distinct shoulder-like swelling, the palpiger (Fig. 18, pg), 

 which bears a two-segmented labial palpus (Fig. 18, lipl). There is a 

 heavy, semicircular, chitinous band (Fig. 18, cb) that surrounds each pal- 

 piger which probably serves to increase its rigidity. Each labial palpus 

 consists of two segments. The proximal segment is short, as wide as long; 

 while the distal segment is conical and bears a group of tactile setae at its 

 distal end. The ligula also bears four to six moderately large setae. The 

 type of ligula found in C. bivulnerus is remarkably constant within the 

 family, the only notable variation being found in Hyperaspis, where the 

 labial palpi have been reduced to a single dome-like segment which bears a 

 few tactile setae (Fig. 27, lipl). 



THORAX 



That part of the body caudad of the head consists of thirteen segments. 

 The dorsal surface of the segments is convex and the ventral surface con- 

 cave or flattened. They may be provided with scoli, senti, parascoli, 

 strumae, verrucae, or chalazae and setae. The variation in the type of 

 armature will be taken up later. The first three segments constitute the 

 thorax and the remainder the abdomen. In all of the genera of the family 

 the thoracic segments are distinctly separated from each other by a deep 

 coria, more distinct on the ventral than on dorsal surfaces. 



Prothorax 



The prothorax of C. bivulnerus (Figs. 1, 2 and 3, prth) is about two-thirds 

 as long as the mesothorax and metathorax combined. The same is true 

 of Epilachna, Microweisea, Scymnus, and Hyperaspis; while in all of the 

 genera of the Coccinellini the prothorax is about one-half as long as the 

 other thoracic segments together. 



The tergum is usually convex and oval in outline when viewed from 

 above (Figs. 1 and 2, I). In C. bivulnerus the greater part of the dorsum 

 is covered with a dark heavily chitinized dorsal shield from which the 

 cone-like senti project. This shield is formed by the fusion of pinacula and 

 its surface bears numerous fine setae. The dorsal shield, when viewed from 

 above, appears to be rectangular in outline and is divided into two parts 

 by a slender white line extending along the dorso-meson. The senti are 

 arranged in three distinct groups, a cephalic group of six placed in a trans- 

 verse row near the cephalic margin, a lateral group of one placed near the 

 middle of each lateral margin, and a caudal group of one placed near the 

 middle of each half upon the caudal margin. In Epilachna the dorsal 

 shield does not cover such a large portion of the dorsum. It is more or 

 less oval in outline and bears only the cephalic row of four scoli. Its sur- 



