1919] Walker: Structure of Orthopteroid Insects 289 



Grylloblattoidea (Grylloblattidae) . 



The female genitalia of the Orthoptera are most nearly 

 approached by those of Grylloblatta, so that we may consider 

 this form next. 



A glance at the end-segments and ovipositor of GryUohlatta 

 (Figs. 31-35) at once recalls the Orthopterous families Gryllidae 

 and Tettigoniidae, except in the segmented cerci, which are 

 more like those of certain Plecoptera, or to a less extent, the 

 Mantidas. The form of the eighth, ninth and tenth segments 

 is very like that of Conocephalus, though more depressed and the 

 tenth segment more prominent. The eighth sternum is not 

 flap-like, but quite generalized in form, although a median pale 

 or thin area is present, which marks the small cavity into which 

 the vagina opens. 



The ninth tergite (Fig. 31) is somewhat prolonged ventrad 

 as in Gryllus, the ventro-cephalic margin being oblique, as is 

 usual in the Tettigoniidas and Gryllidas. The tenth tergite in 

 the adult female is fused with the sternite forming a complete 

 ring, as in many Plecoptera. Its dorsum is slightly prolonged 

 behind the bases of the cerci, but does not overlap the supra- 

 anal plate, which is quite distinct, though small. Both supra- 

 anal plate and paraprocts, which are subchitinized, are quite 

 like those of many Tettigoniidae. The spiracles, which are 

 very small, are all situated in the pleural membrane. 



In the external form of the valvulee and their connections 

 with neighboring sclerites Grylloblatta is remarkably like a 

 primitive Tettigoniid, such as Ceuthophilus. The most con- 

 spicuous, but not the most important difference is in the 

 basivalvulae, which are more clearly defined and more heavily 

 chitinized, recalling those of the Mantids. The valvifer has 

 exactly the same relations as in the Tettigoniidas. Its lower 

 angle articulates with -the ecto-basal angle of the ventral 

 valvula, not being prolonged under the subgenital plate as in 

 Gryllus and Oecanthus. There are well-marked internal ridges, 

 along its upper and lower margins, the latter being continuous 

 with the ninth tergal apodeme, all these features recalling 

 Ceuthophilus or Conocephalus strongly. 



The ovipositor is much like that of Ceuthophilus or related 

 genera, though the valvulae are less compressed and not so 

 closely applied to one another, the ventral ones, particularly. 



