240 NORTH AMERICAN BLATTIDAE 



supra-anal plate is not decidedly produced, the genital hook is 

 curved outward and the subgenital plate is extraordinarily special- 

 ized; in the female, the tarsal joints of the caudal limbs scarcely 

 reach beyond the apices of the distal caudal tibial spines. 



The species of this genus are small. Both sexes are more hir- 

 sute than in Arenivaga and, as in that genus, the apterous females 

 show this feature to a decidedly greater degree than the males. 



Eremoblatta subdiaphana (Scudder) (Plate IX, figures 17 to 20.) 



1902. Ilomoeogamia subdiaphana Scudder, Proc. Davenport Acad. Sci., ix, p. 19. 



[c?; Las Cruces, New Mexico.] 

 1909. Homoeogamia subdiaphana vwhavcnsis Rehn and Hebard , Proc. Acad. Nat. 



Sci. Phila., 1909, p. 415. [ o" ; Cottonwood, California.] 



This insect, by the numerous generic characters given above, 

 may be readily separated from the species of Arenivaga. In 

 addition, the decidedly glassy tegmina, which even in specimens 

 of the maximum intensive coloration are never maculate, and the less 

 oblique discoidal sectors, give males of the present species a dis- 

 tinctive appearance when compared with any other species of 

 the subfamily here considered. 



The maximum of recessive coloration is found in material of this 

 species from the Gila-Mojave Desert region; and as the name 

 mohavensis was proposed for this condition, we consistently place 

 it in the synonymy here. 



The following features are observed in the male sex. 



(Alamogordo, New Mexico.) Interocular width slightly greater than that be- 

 tween the ocelli, rarely these dimensions are subequal. Ocelli decidedly produced, 

 with face below these very deeply concave. Pronotum transverse, with cephalic 

 margin broadly, and caudal margin weakly, convex. Tegmina with a decided glassy 

 luster. Discoidal sectors of tegmina weakly oblique. Supra-anal plate transverse, 

 deplanate and weakly produced between the cerci, with distal margin weakly con- 

 vex. Immediately above the cerci, on each side, a narrow, transverse portion of 

 this plate is convex and thickly covered with hairs. Cerci short, not articulate, 

 proximal half stout; distal half abruptly narrower, directed at an angle to the prox- 

 imal portion, more delicate in structure and irregularly rounded. Concealed genital 

 hook elongate, base soft, becoming gradually corneous, proximal portion tubular, 

 straight, curving slightly inward distad; distal portion flattened, tubular, curving 

 regularly and sharj^ly outward, not enlarged, with sharp apex directed proximad. 

 From the l)asc' of this organ another soft integument is produced inward, becoming 

 corneous distad, in the form of an elongate, sharp spike, which organ is of nearly 

 equal length to the genital hook. Dextro-dorsal concealed genital plate small. 



