1922] Walker: Structure of Orthopteroid Insects 35 



covered with minute, regularly arranged spinules. They are 

 continuous with the dorsal lobes, which are black and more 

 heavily chitinized, with sharp, excavated margins, apparently 

 serving as titillators. In M. femnr-rubrum the dorsal and 

 ventral lobes are comparatively free from one another and 

 the former project dorsad in the form of slender, sharp-pointed 

 processes of irregular form, while in M. hivittatus (Figs. 55, 56), 

 the dorsal lobes are much shorter and are folded within the 

 ventral lobes in a complex, scroll-like fashion. There is a 

 strongly chitinized bridge connecting the dorsal lobes with the 

 arch of the endapophyses. In place of the subventral lobe 

 there is only a pair of soft, irregular folds of integument. The 

 expanded bases of the endoparameres are much more strongly 

 divergent than in Dissosteira. 



The genitalia of the Acrydiidas are astonishingly unlike 

 those of the Acrididas, though occupying a similar position, the 

 outlet of the penis having a suberect position and the post- 

 sternite lying far forward under the paraprocts. It is evident 

 that the genitalia of this family have undergone a marked 

 degeneration of structure. Three genera were examined: 

 Tettigidea {T. lateralis parvipennis Hafr.), Acrydhim {A. 

 ornatum Say and A. granulatum Kirby) and Paratettix (P. 

 cuciillatus Burm.) 



In Tettigidea the pseudosternite is V-shaped, recalling that 

 of Ceuthophilus maculatus Harr., except that, instead of the 

 upright position of the latter, the arch is tilted forward so as 

 to be almost horizontal. It becomes evident on seeing the 

 pseudosternite in this form, ■ that the forward tilting of this 

 sclerite has taken place in all the Acridoidea and is an expression 

 of the same process of shifting that has brought about the 

 upright position of the genital outlet. The recurved apex of 

 the pseudosternite in Tettigidea is armed with a group of 

 spines. 



Behind and between the arms of the pseudosternite are two 

 narrow plates, which curve inward and terminate behind in a 

 pair of lobes on each side of the genital aperture. These plates 

 appear to be the rami, but the endapophyses, so strongly 

 developed in the Acrididae are entirely absent. The genital 

 aperture is wide with folded membranous walls, and near the 

 termination of the ejaculatory duct is a dilatation which rep- 

 resents the spermatophore sac. There are no traces of the 



