243] THE LARVAE OF THE COCCINELLIDAE—GAGE 11 



latere- ventrad and become obsolete dorsad of the antennal fossae. Due 

 to the extreme length of the head in this genus, these arms are very long. 

 In Scymnus the epicranial arms are entirely wanting. 



The two proximal unpaired sclerites between the arms of the epicranial 

 suture in Corydalis are the fused front and post'clypeus. These areas are 

 separated from each other in the more generalized forms by the fronto- 

 clypeal suture; in the specialized forms, however, they may become com- 

 pletely fused. In such cases the fronto-clypeal suture is absent, but por- 

 tions of it may be indicated by a furrow on each lateral portion of the head. 

 These portions extend mesad from near the precoila. In C. bivulnerus 

 and all coccinellid larvae the front and post-clypeus (Fig. 6, fc) are com- 

 pletely fused and the fronto-clypeal suture is wanting. The clypeal suture 

 (Fig. 6, cs) is indicated by an indistinct furrow extending mesad from the 

 precoila (Figs. 5 and 6, pel). The area ventrad of this furrow in the pre- 

 clypeus (Fig. 6, pc) and the area dorsad of it is the fused front and post- 

 clypeus (Fig. 6, fc). In Epilachna (Fig. 4) the front and postclypeus are 

 entirely separated from the preclypeus by the complete clypeal suture; 

 while in all of the other genera of the family that were studied the condi- 

 tion of the cljqjeal suture is approximately that found in Chilocorus. 



The labrum of C. bivulnerus is the distinct, slightly chitinized, shield- 

 like sclerite attached to the ventral margin of the preclypeus (Fig. 6, /). 

 The ventral margin of the labrum may be slightly emarginate and usually 

 bears four or six medium-sized setae. In general the structure of the 

 labrum in all of the coccinellids studied approximates very closely the con- 

 dition found in the labrum of C. bivulnerus. Its general shape, however, 

 varies in the different genera of the family. In the genus Epilachna the 

 labrum varies most widely from the Chilocorus type. In this genus it is 

 broadly transverse and widely but shallowly emarginate on the ventral 

 margin. 



The vertex of C. bivulnerus (Fig. 6, v) consists of the paired continuous 

 areas on the cephalic and dorsal aspect of the head. In Chilocorus, 

 Epilachna, and Megilla the epicranial stem is present and marks the line 

 of separation of the two halves of the vertex; in Hippodamia, Coccinella, 

 Anatis, Adalia, and Microweisea the epicranial arms alone are present and 

 the two halves of the vertex do not meet on the meson, but a portion of the 

 front extends between them to the occipital foramen. In Hyperaspis and 

 Scymnus the epicranial suture is absent and the front, postclypeus, and 

 vertex are fused. The vertex is continuous on its lateral and caudo- 

 lateral margins with the genae (Fig. 5, ge), the region of the vertex ventrad 

 and mesad of the ocelli and the antennal fossae. The size, shape, and 

 extent of the vertex is dependent upon the location and extent of the epi- 

 cranial suture. 



