20 ILLINOIS BIOLOGICAL MONOGRAPHS [252 



members of the Coccinellini and Epilachna; while in Micro weisea, Scym- 

 nus, and Hyperaspis the mesothoracic spiracle is not located on the tergum, 

 or protopleurite, as Boving points out, but distinctly in the mesocoria. 

 The metathoracic spiracles are rudimentary or entirely wanting. 



Appendages 



The thorax of all coccinellid larvae bears three pairs of legs. One pair 

 is attached to each segment. They are well developed and fitted for walk- 

 ing or clasping the surface of the leaves and stalks upon which the larvae 

 are usually found. Since the general form and structure of each pair of 

 legs is the same, their only difference being that of size, a description of a 

 single prothoracic leg will suffice for all. The mesothoracic and meta- 

 thoracic legs are subequal and slightly longer and wider than the pro- 

 thoracic legs. Each leg is about as long as the body is wide, except in 

 very young larvae in which they are distinctly longer. In adult larvae 

 they are comparatively stout and fitted for clasping. The coxal fossae 

 are the circular or oval holes in the sternum in which the legs are inserted. 

 The coxa are attached to the coxal fossae by a distinct membrane, the 

 coxacoria. There is a distinct coxacoila on the lateral margin of each 

 coxal fossa in which the coxa articulates. The procoxa (Figs. 2 and 3, 

 pre) is subcylindrical, short, tapering toward the distal end and bears a 

 few scattered but prominent setae. The protrochanter (Figs. 2, 3, prtr) 

 is short, triangular, the ventral surface the longer and bears a prominent 

 group of coarse setae. The profemur (Fig. 3, prfr) is short, about twice as 

 long as wide, with its dorsal, caudal, and cephalic surfaces sparsely setace- 

 ous. This condition of the femur is found in Chilocorus and Hyperaspis; 

 while in Epilachna and all of the genera of the Coccinellini, and the genera 

 Microweisea, and Scymnus, the femur is at least three times as long as wide. 

 The protibia (Figs. 2, 3, prti) is about as long as the profemur, one-third 

 as wide as long, and tapering distinctly toward the distal end. The 

 cephalic, caudal, and dorsal surfaces of the proximal two-thirds are densely 

 setaceous; while the entire surface of the distal one-third is densely covered 

 with club-shaped setae or tenent hairs (Fig. 43, te). The tenent hairs are 

 very numerous in Chilocorus, Epilachna, and all of the genera of the 

 Coccinellini; while in Scymnus and Hyperaspis there are only a few, five 

 to ten, on each tibia, and in Microweisea there are only two which are very 

 broad, flat, elongated, and paddle-like (Figs. 44, 45). The protarsus 

 (Figs. 2, 3, prta) consists of a single short triangular segment which bears 

 a few tenent hairs. Its distal margin is provided with a sickle-shaped 

 claw (Figs. 4, 3, prcl). This claw is provided with a short, blunt appendic- 

 ulated tooth on its proximo-ventral angle, and it probably serves as an 

 aid in clasping surfaces. There is some variation in the general shape 

 of the tarsal claw in the various genera of the family and this characteristic 

 serves as a means of separating them. 



