4 SMITHSONIAN MISCELLANEOUS COLLECTIONS \0L. 94 



beyond the tergum, and its posterior margin is reflected into the floor 

 of the genital chamber beneath the base of the ovipositor. In the male 

 (fig. 33 A) the abdomen terminates ventrally with the ninth sternum, 

 which is much enlarged and subdivided into a proximal sternal plate 

 (IXS) and a distal sternal lobe (IXSL). The terga of the ninth and 

 tenth segments are narrow (figs, i, 33 A) and are united with each 

 other in both sexes. The tenth tergum of some species bears a pair 

 of small median processes, known as the furculae, projecting backward 

 from its posterior margin (figs. 38 A, B, 39, /). The ventral part of 

 the ninth segment in the female is reduced to a narrow median space 

 between the bases of the dorsal prongs of the ovipositor, and the venter 

 of the tenth segment is a small membranous area above the base of 

 the ovipositor. In the male the venter of the tenth segment is con- 

 tained in the membranous dorsal wall of the genital chamber (fig. 24 A, 

 X.V). The eleventh segment is the conical end piece of the body 

 formed of a triangular dorsal plate, the epiproct (fig. i, Eppt), and of 

 two lateroventral plates, the paraprocts (Papt). Between the apices of 

 these plates is the anus. The appendicular cerci (Cer) arise laterally 

 on the base of the eleventh segment from membranous areas between 

 the adjoining angles of the epiproct and paraprocts. The exposed 

 part of the female ovipositor consists of four short, strongly sclero- 

 tized prongs (Ovp) projecting backward from the ventral parts of 

 the eighth and ninth segments. The complex copulatory apparatus of 

 the male (fig. 33 B) is ordinarily concealed within a genital chamber 

 between the terminal lobes of the eleventh segment and the upturned 

 lobe of the ninth sternum (fig. 24 A). 



The abdomen of Tetrigidae is in general similar to that of the Acri- 

 didae, though it difi^ers from the latter in several respects. The tergum 

 of the first segment (fig. 2 C, IT) is solidly joined to the thorax, but 

 the sternum (D, IS) has a flexible connection. Tympanal organs are 

 absent. The first spiracles (C) are contained in the first tergum, but 

 the other spiracles lie in membranous lateral areas of the dorsum 

 beneath the lower edges of the terga, though the last two on each side 

 (fig. 18 A) are contained in weakly developed laterotergal sclerites. 

 Between the spiracles and the sterna of segments // to VII there is on 

 each side a series of small laterosternal, or " pleural," sclerites (fig. 

 2 C, 1st) best developed anteriorly, where there are two sclerites in 

 segments // to IV. The terminal segments of the tetrigid abdomen, 

 in both the female (fig. 18 A) and the male (fig. 27 A), are essentially 

 the same as those of Acrididae, and the female ovipositor (fig, 18) 

 has little to distinguish it from the acridid ovipositor. The phallic 



