1919.] NATURAL SCIENCES OF PHILADELPHIA. 59 



longitudinal dorsal dark bar of variable strength and complete- 

 ness, this always indicated in texana and carried over the anal 

 field of the tegmina, leaving the anal angle pale. This medio- 

 longitudinal line may be merely a lining of the median carina 

 of the pronotum, or a pair of arcuate lines on the head. The 

 tegmina in certain species (i. e., hivittata and both races of maciili- 

 pennis) may show a maculate pattern of variable intensity. In 

 all the species except M. hivittata the tegmina show a decided 

 pale subcostal line on the proximal half in both sexes, while in 

 hivittata the male sex is without such a line, although the female 

 is marked as in the other species. In M. neo-mexicana and alacris 

 the pale subcostal line broadens out into a wash which colors a 

 very considerable portion of the tegmina, but its correlation with 

 the subcostal line is evident. Occasionally the pale subcostal 

 line is weak, but we have never seen it absent in any individuals 

 but males of hivittata. The dark postocular lateral bars on the 

 pronotum encroach upon the dorsal surface of the pronotum in 

 numerous individuals of maculipennis, and in texana, neo-mexicana 

 and alacris the dark postocular bars are bordered with yellowish. 

 The lateral facial carinas are similarly marked in the same species, 

 and the face is variably infuscate in texana, neo-mexicana, alacris 

 and intertexta. 



Groups. — The genus comprises three groups, which at first 

 glance appear more different than a detailed analysis indicates. 

 One of these contains texana alone, another is made up of neo- 

 mexicana and alacris, with intertexta an aberrant member approach- 

 ing the third group, which is composed of hivittata and maculipennis. 

 If the features separating these groups were more decided, or 

 their differentiation more clearly indicated, it would be advisable 

 to use subgeneric names for them, but this is not desirable, owing 

 to the relatively slight divergence of the species, judging from 

 external morphological features. 



The groups and their chief features are: 



Group A (texana) Form relatively robust. Lateral fove- 



olse .obsolete. Antennae moderately 

 heavy. Pronotum short. Lateral 

 carinae of pronotum distinct, diverg- 

 ing caudad. Supplementary carinae 

 on lateral lobes of pronotum distinct. 

 Caudal limbs relatively robust. (Col- 

 oration distinctive.) 



