MORGAN HEBARD 219 



C. Size rather small. Pronotum strongly transverse. Tegmina with weakly 

 oblique discoidal sectors. From base of concealed genital hook, s[)rings an- 

 other appendage of equal length, with acute, elongate, chitinous apex. 



Eremoblatta subdiaphana (Scudder) 

 CC. Size very small. Pronotum very weakly transverse. Tegmina with 

 longitudinal discoidal sectors. From base of concealed genital hook, springs 

 another appendage, with acute, abbreviate, chitinous apex. 



Eremoblatta hirsuta new species 



Other features, requiring more detailed discussion and in con- 

 sequence omitted from the above key, offer further aid in separating 

 some of the more closely related species. The male concealed 

 genitalic features are distinctive in each species, but can only be 

 properly studied when the subgenital plate has been removed. 



Key to the North America?! Species of the Polyphaginae {based on 



females) 

 Females are much heavier and broader than the males of the 

 respective species and have the limbs decidedly heavier, with 

 homologous spines relatively heavier and longer. In the females 

 the length of the tarsal joints is decidedly reduced to varying 

 degrees. As this sex is evidently a decidedly less specialized con- 

 dition, much fewer specific differential characters are to be found, ''■^^ 

 though remarkable generic differences exist. 



A. Head somewhat similar to that of male, but larger and broader, with interocular 

 space much greater and ocelli absent. Tegmina present, of length of abdomen, cor- 

 neous, the surface densely shagreenous; wings represented by brief pads. Sub- 

 genital plate valvular, compressed and decidedly produced meso-distad, with a 

 percurrent, linear, medio-longitudinal sulcus, the nearly vertical sides of the valves 

 longer than wide and roughly trigonal, their basal sutures convergent to their 

 acute-angulate juncture ])roximad. Cephalic femora with ventro-cejihalic margin 

 hairy, these hairs more closely set, shorter and stouter distad, suggesting chaeti- 

 form spines, terminated distad by a heavy, elongate sjiine. 



Homoeogamia mexicana (Burnuister) 



AA. Head remarkabK' different from that of male. Tegmina and wings absent. 

 Subgenital jilate broadly convex in general form, witht)ut a sulcus or any decided 

 production meso-distad. Cephalic femora lacking a distal si)ine. 



^^ Indeed, as may be seen in the key, none of the characters which separate females 

 of Arenivaga rehni, erratica and apacha are sufficiently decided to enable one, not familiar 

 with females of the three species, to determine occasional individuals of this sex with 

 certainty. 



MEM. AM. ENT. SOC, 2. 



