club-shaped, at times warty or tuberculate, the third very 

 small and round, drawn out in the form of a long bristle 

 or seta. In the genus Otiocerus, there are one or two 

 flattened arid twisted, basal appendages. 



The thorax. The pronotum is variable in length, at 

 times narrow, fitting up close to the head collar-fashion, 

 nearly always with three longitudinal carinae which are at 

 times very indistinct. The mesonotum or scutellum, as it 

 is generally called in this family, is usually large and long, 

 more or less triangular, and with from three to five long- 

 itudinal carinae. 



The elytra. The wing covers or elytra may be either 

 brachypterous, in which form they are short, not reaching 

 or scarcely attaining the tip of the abdomen, more or less 

 rounded and leathery, with prominent or scarcely visible 

 nervures, or else macropterous when they are longer than 

 the abdomen, transparent or translucent, with definite, 

 punctate or setigerous nervures. In some genera the wing 

 covers are convexly arched. 



There are two distinct regions, an inner, small and tri- 

 angular claims and an outer longer area known as the 

 corium, the two being separated by a claval suture. In- 

 completely developed elytra often show no trace of this 

 suture. The inner margin is known as the commissural 

 margin and the outer as the costal or external margin. A 

 single forked nerve occupies the clavus. The corium is 

 traversed by a more or less large number of longitudinal and 

 transverse nervures; there are two or three main nerves, 

 originating at the base, and these are called sectors, the 

 term embracing the main nerve and all of its branches. 

 They are known as the first, second, and third sectors, 

 numbering from the costal margin. The wings are trans- 

 parent hyaline, and in certain genera are either vestigial 

 or entirely lacking. 



The abdomen. The abdomen is composed of eleven seg- 

 ments, each formed by the union of two horny, chitinous, 

 arched plates that fit into each other and are held together 

 by a membrane; the dorsal plates or tergites and ventral 

 plates or sternites are held together by the connexivum. 



The abdomen is generally more or less conical, and 

 narrowed behind but in many species is somewhat flat- 



18 



