40 PROCEEDINGS OF THE NATIONAL MUSEUM vol.89 



But in the structure of the mesosternum and mesocoxae, which points 

 seem to be the most trenchant in separating Ewparixia from Afaenius, 

 it is a typical Ataenius. 



Genus EUPARIXIA Brown, 1927 



Euparixia Brown, 1927, Can. Ent., vol. 59, p. 288. — Hinton, 1934, Pan-Pac. 

 Ent, vol. 10, p. 27; 1936, Univ. California Publ. Ent., vol. 6, p. 274. 



Type of genus: Euparixia dimcani Brown, 1927 (by monotypy). 



This genus was established to contain species of Aphodiinae having 

 the prothorax strongly constricted at base, the middle coxa obliquely 

 truncate at outer extremity where it is contiguous with or overlapped 

 by the elytral margin, and the anterior femur unusually short and 

 broad. 



Since the publication of the original diagnosis, two species, 

 E. formica and E. costaHcensis^ have been added by Hinton, and in 

 this paper a fourth is described. One of these is known to be as- 

 sociated with ants of the genus Atta^ and it is probable that such is 

 the habit of all the species. At least it is noteworthy that the known 

 range of Euparixia is included within the range of Atta. 



1. EUPARIXLA. BRUNERI, new species 



Body uniformly castaneous, legs somewhat darker. Anterior 

 margin of head truncate across middle, sides feebly curved to the 

 prominent genal lobes. Front finely and rather densely punctured 

 in upper portion, finely granulated near margin, central area smooth 

 and slightly raised. Vertex coarsely and very densely punctured. 

 Pronotum broader than long, without well-defined marginal groove, 

 much narrower across base than width of elytra across humeri, 

 posterior angles completely obliterated, greatest width at about an- 

 terior third, in front of which point the sides are broadly explanate, 

 anterior angles prominent but broadly rounded. Surface in basal 

 half very coarsely and rather densely pitted, anterior half across 

 disk coarsely to finely punctate, explanate margins almost impunc- 

 tate. Elytra together suboval, widest across apical third, basal ends 

 of lateral cariniform margin ending in a prominent spur, scutellum 

 elongate triangular, very narrow, striae shallow^, strial punctures 

 coarse and quadrate, intervals acutely carinate. Lateral margin 

 acute, epipleura nearly smooth. Pygidial carina feeble with very 

 weak median cusp. Metasternum mostly smooth, median area with 

 a few coarse ill-defined punctures adjacent to middle coxae, median 

 groove shallow. Abdominal sternites with a few very large, shallow, 

 ill-defined pits, the pits of the basal transverse rows very large, quad- 

 rate and contiguous. Anterior femur short and very broad, an- 

 terior margin with broad groove, surface moderately coarsely and 



