1903.] NATURAL SCIENCES OF PHILADELPHIA. 181 



BB. — Marginal field of tegmina narrow; tarsi very slender and 

 elongate; metatarsi of median limbs about as long as 



the tibiae, Arenivaga n. subg. 



AA. — Supra-anal plate of male very broadly emarginate apieally; 

 median and posterior tibiae ^v-ith seven apical spines ; vertex 

 with a distinct angular transverse ridge, 



Eremoblatta n. subg. 



Key to the species {based on the males). 



A. — Supra-anal plate of male bilobate. 

 B. — Marginal field of tegirdna broad. 



c. — Elytra tessellate, never tuberculate; veins in the distal 

 portion of the discoidal field longitudinal, 



mexicana Burmeister. 

 cc.^ — Elytra sparsely tuberculate at base; veins in the distal 

 portion of the discoidal field arcuate, azteca Saussure. 

 BB. — Marginal field of tegmina narrow. 



c. — Interspace between the eyes narrower than that be- 

 tween the ocelli. 

 d. — Size rather large (length including tegmina 23-29 



mm.), holliana Saussure. 



dd. — Size small (length including tegmina 19-21.5 mm.), 



erratica n. sp. 

 CO. — Interspace between the eyes not narrower than that 



between the ocelli, apacha Saussure. 



A A. — Supra-anal plate of male very broadly emarginate, 



subdiaphana Scudder. 



Subgenus HOMCEOGAMIA sen. strict. 



Suhgeneric Characters. — o' . Size rather large; form gracefid. Teg- 

 mina elongate with the lateral margins sub-paraUel; marginal field 

 broad, equal to one-third of the sub-basal width of the tegmina ; veins 

 in the distal portion of the discoidal field arcuate transverse. Tarsi 

 comparatively robust; metatarsi of median hmbs about half as long 

 as the tibia?. 



9 . Size large; form obese. Tegmina broad, but shghtly exceeding 

 the abdomen in length, the lateral margins parallel in the distal half. 

 Metatarsi of median limbs not half as long as the tibiae. 



Homceogamia mexicana Burmeister. 



1838. Heterogamia (Homoeogamia) mexicana Burmeister, Handb. d. Entom., 



Bd. II, Abth. II, pt. 1, p. 490. LMexico.] 

 1864. Polyphaga {Homceogamia) Mexicana Saussure, Mem. I'Hist. Nat. 



Mexique, IV, p. 226. [Warm lands of the Eastern Cordillera; Orizaba, 



Mexico.] 



'■ The distinguishing characters of the male of H. azteca are taken from Saussure, 

 as that sex has never been examined bv the author. 



