22 Annals Entomological Society of America [Vol. XV, 



this plate in the Acrydiidse, described in the account of the 

 females, is present also in the males; and the cerci in this family 

 are also similar in the two sexes. In the Acrididae they are 

 usually larger in the male, serving as claspers in copulation, 

 although often but little modified. In the Acridin^ and 

 Oedipodin^, e. g., they are small, simple and styliform, while 

 in the Locustinae they assume a considerable variety of forms, 

 sometimes being forcipate, as in the Old World genus Colliptamtts, 

 but never, so far as I am aware, armed with teeth or spines, as in 

 the Tettigonoidea. There is a distinct cereal basipodite in all 

 of the forms examined. The paraprocts are broad and flat 

 as in the females. 



The structure of the ninth sternum is very peculiar. It is 

 very large, externally convex and upturned, and divided 

 transversely as in the Phasmoidea, the distal plate, commonly 

 known as the subgenital plate, possibly representing the fused 

 coxites. This plate has sometimes been mistermed the tenth 

 sternite. Its margin forms the rim of a deep genital cavity, 

 roofed over by a fold of integument, the pallium, which is 

 continuous with the sternal margins, and together with the 

 paraprocts, usually completely conceals the genitalia, although 

 in some species in which the penis is very long the pallium is 

 pushed up into a conical form, the tip of the penis being exposed. 

 In the Acrydiidce the pallium is more firmly chitinized than 

 in the Acrididae, its dorsal surface being covered with a pair 

 of plates separated by a median groove. In Acrydium (Tettix) 

 and Paratettix there lie in this groove two slender rods, which 

 terminate near the front margin in a pair of small hooks, 

 resembling titillators and probably serving a similar purpose, 

 the usual titillators (parameres) being absent in this family 

 (PI. VI, Fig. 60). In Tettigidea {T. lateralis parvipennis Harr., 

 PI. VI, Figs. 58, 59) these hooks are absent, but the pallium is 

 still more heavily chitinized than in Acrydium, being a decidedly 

 plate-like structure, divided into right and left parts by a median 

 suture. Morphologically the pallium is part of the primitive 

 floor of the genital cavity. Styli are absent in the Acridoidea, 

 although there are some forms, like Acrydium, in which two 

 small tubercles on the caudal margin of the ninth sternum are 

 somewhat suggestive of vestigial styli. 



