257] THE LARVAE OF THE COCCINELLIDAE— GAGE 25 



form from the true scolus and has been called a sentus. Senti are found 

 in Chilocorous and Anatis. In the latter genus the senti are short and 

 thick. 



A pinaculum is the more or less chitinized plate which surrounds the 

 base of a scolus, sentus, or parascolus (Figs. 28, 29, 30). It usually bears 

 numerous, small, dark-colored setae. Several pinacula may become fused 

 to form the shield-like plates of the body. 



A chalaza is a distinct but slight pimple-like projection of the body-wall. 

 It may be considerably wider than long and bears on its distal end a stout 

 seta (Fig. 33). Chalazae are present in practically all coccinellid larvae. 

 They are for the most part found on the sternum and in some cases on 

 the lateral aspect. In Microweisea distinct chalazae are found on the 

 dorsal aspect of the abdomen, there are also distinct chalazae on the dorsal 

 shield in most of the genera of the family. 



A struma is a parascolus which has become shortened, usually appearing 

 to be nothing more than a distinct mound-like projection of the body-wall 

 (Fig. 31) upon which are situated a few chalazae. This structure was for- 

 merly called a tubercule, but this term is misleading and has been applied 

 by various workers to most any kind of an extension of the body-wall. 

 In order to avoid further confusion the term struma is proposed for this 

 structure. Strumae are found in the armature of the abdomen of Adalia 

 and Megilla. 



The struma becomes much reduced in some of the more specialized 

 larvae so that it appears to be mound-like and bears setae instead of 

 chalazae (Fig. 32). This structure has also been called a tubercule by 

 some workers and by others a verruca. Since the term verruca is not 

 misleading or conflicting, it should be restricted to structures such as these. 

 Verrucae are found in the armature of Scymnus and very small indistinct 

 ones in Microweisea; the latter genus also bears chalazae. 



In the most specialized of the coccinellids verrucae and chalazae have 

 become so greatly reduced that the setae are not elevated above the 

 general surface of the body (Fig. 34). Setae are found on the body of all 

 of the more generalized coccinellids, but it is only in the more specialized 

 groups that the setae constitute the only type of armature. The Hyper- 

 aspini is the only tribe that I have studied which has this condition. 



In the more generalized genera the armature of the body consists of 

 scoli arranged upon the dorsal and lateral surfaces. Such a condition as 

 this is found in the subfamily Epilachninae. In Chilocorous and Anatis 

 the scoli are replaced by senti on the dorsal and lateral aspects and on these 

 regions in Hippodamia, Coccinella, and to a small extent in Adalia para- 

 scoli are present. The projections of Adalia seem to show a stage of 

 transformation between parascoli and strumae; for parascoli are found on 

 the dorsal surface and strumae on the lateral. Strumae are found on the 



