18 PROCEEDINGS OF THE NATIONAl, MUSEUM vol. loi 



MYOCHROUS AUSTRINUS, new species 

 Plate 1, Figure 5 



About 5.5 mm. in length, elongate oblong, shining piceous with a 

 bronzy luster, prothorax 3-toothed and rather convex, as in M. cyphus^ 

 with dense, often confluent, moderately coarse punctation, the brown 

 and white scales not so dense as to hide completely the sculpture, and 

 not closely appressed but curving. 



Head densely covered with scales to antennal sockets, the punctures 

 beneath coarse and dense ; in some specimens traces of a median line 

 down front, the usual occipital ridge on either side. Antennae yel- 

 lowish or reddish, of the usual proportions. Prothorax wider than 

 long, conspicuously 3-toothed on lateral margin with a tooth at apical 

 and basal angles ; disk with a median convexity and a basal depression 

 along the margin, most pronounced over the scutellum; punctation 

 moderately coarse and confluent, in longitudinal lines, not entirely 

 concealed by the yellowish-gray scales. Elytra with small humeral 

 prominences and a basal callosity with a depression below in which 

 the punctures are transversely ridged; punctures coarse and closely 

 placed, becoming much finer and less dense toward apex; scales not 

 entirely concealing punctation, not very coarse or closely appressed 

 but curved. Body beneath shining with a bronzy luster beneath the 

 rather fine white scales, tip of abdomen reddish, first abdominal seg- 

 ment moderately coarsely and densely punctate. Hind femora bluntly 

 toothed, anterior tibiae with the usual inner tooth. Length 5 to 

 5.8 mm. ; width 2.2 to 2.3 mm. 



Type.— A female, U.S.N.M. No. 59027, collected at 2,300-2,500 feet, 

 July 13 to 15, by H. F. Wickham. 



Type locality. — Tucson, Ariz. 



Other localities. — Arizona : San Bernardino Ranch, Cochise County, 

 3,700 feet (F. H. Snow; two specimens in Snow collection at Kansas 

 University, one specimen in the Museum of Comparative Zoology at 

 Cambridge). 



Remarks. — At first glance this species might be confused with 

 M. cyphus because of the slight convexity on the thorax. The curved 

 and not closely appressed scales and the more coarsely punctate thorax 

 distinguish it from that species. This may very well be a Mexican 

 species slowly extending into Arizona. A series of specimens from 

 Los Mochis, Sinaloa, Mexico, collected by C. T. Dodds on June 27, 1922, 

 in the collection of the California Academy of Sciences, appears to be 

 the same as the Arizona specimens. There is, unfortunately, no male 

 among the four Arizona specimens for comparison of the aedeagi. 

 A drawing of the aedeagus of a male from Los Mochis, Mexico, is 

 given, showing it to be similar to both M. cyphus and M. denticollis 

 in the structure of the soft membranes, but larger than either. There 



