94 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
Genus MASTOGENIUS Solier. 
Mastogenius Souier, Gay’s Hist. Chile, Zool., vol. 4, 1849, pp. 507-508. 
This genus contains 13 species, 1 of which is described as new in 
the present paper. Of the previously described species, 5 are found 
in the United States, 5 in South America, 1 in the West Indies, and 
1 in Africa; the latter may not be congeneric with the species found 
in America. 
MASTOGENIUS CYANEOUS, new species. 
Elongate, subparallel, uniformly dark blue above, except the scu- 
tellum, which is piceous; beneath piceous. 
Head convex, without any median depression; surface rather 
densely, deeply, and coarsely punctate, with the intervals finely, 
reticulate; eyes distinctly closer on the occiput; antennae reaching 
to middle of pronotum, serrate from the fourth joint, second joint 
short, globose, third joint about as long but much narrower than the 
second, slightly shorter than the fifth, and scarcely half as long as the 
fourth. Pronotum regularly convex, about one and one-half times 
as wide as long, distinctly narrower in front than behind, widest at 
the middle, sides feebly arcuate from base to apical fourth, then 
strongly, arcuately converging to the anterior angles; posterior angles 
feebly obtuse; anterior margin feebly, arcuately emarginate when 
viewed from above; base truncate; surface densely and coarsely punc- 
tate ‘similar to that of the head, the punctures deep and regularly 
placed, and from each arises a very fine, rather long, recumbent hair; 
intervals finely reticulate. Scutellum ogival form, smooth. Elytra 
strongly convex, as wide as pronotum at base; sides nearly parallel 
to apical third, then arcuately attenuate to near the apex, where 
they are feebly sinuate, the tips strongly gibbose, and separately, 
broadly rounded; humeral angles obtusely rounded; surface with a 
deep transverse depression at the base, and a broadly obsolete one 
behind the humeri, rather coarsely punctate, and with the punctures 
a little more widely separated, and the pubescence finer and more 
obsolete than on the pronotum; intervals nearly smooth. Abdomen 
beneath strongly convex, sparsely, finely punctate and sparsely 
clothed with short, recumbent, cinereous hairs; intervals finely reticu- 
late; last segment broadly rounded at apex. Prosternum and meta- 
sternum coarsely and rather densely punctate, the punctures very 
deep and well separated on the prosternal process; prosternum with- 
out antennal cavities. Posterior margin of hind coxal plate feebly 
sinuate. 
Length, 2.75 mm.; width, 1.75 mm. 
Type locality —Ancon, Canal Zone, Panama. 
Type.—Cat. No. 25133, U.S.N.M. 
Described from a single specimen collected by E. A. Schwarz, May 
5, 1911. 
