BEETLES OF THE GENUS MYOCHROUS — BLAKE 63 



MYOCHROUS CALCARIFERUS, new species 



Plate 8, Figitbe 1 



Between 4 and 5 mm. in length, elongate oblong, black, with the 

 thorax approximately as long as wide, concealing head, and elytra more 

 than twice as long as thorax; scales on thorax and elytra wide and 

 forming a distinct brown and white pattern; punctation of thorax 

 dense; front tibiae with only a faint trace of toothing before the 

 apex, middle and probably also the hind tibiae in male (males not 

 seen) , with a distinct spur before the apex. 



Head concealed from above by overhung anterior margin of pro- 

 thorax, occiput with trace of ridging on either side, not entirely 

 covered by scales but showing the alutaceous surface beneath ; scales 

 broad, curved, and not flatly appressed, between antennal sockets 

 finer and transversely placed; labrum and antennae reddish brown. 

 Antennal joints of the usual proportions. Prothorax approximately 

 as long as wide with a convex projected anterior margin; a faint 

 transverse depression behind eyes ; sides 3-toothed, surface alutaceous 

 with dense and not coarse, round punctures not entirely concealed 

 by the broad brown and white curved scales, scales forming a pattern. 

 Elytra more than twice as long as thorax, shining bronzy black be- 

 neath the broad brown and white scales ; striate punctures coarse but 

 not ridged, basal callosities not pronounced, a faint depression below ; 

 scales forming a pattern with the humeri and sides more or less white 

 and a white spot near apex. Body beneath finely alutaceous but 

 moderately shining, breast and first abdominal segment not coarsely 

 punctate, with scattered fine white scales; front tibiae with a very 

 obscure tooth before apex on the inner side and a more marked one 

 at apex on outer edge; middle tibiae of female with a distinct spur 

 before the apex, probably also one of the hind tibiae of male although 

 no male examined. Length 4.3 to 4.8 mm. ; width 1.8 to 2 mm. 



Type and paratypes. — Type female in the Miguel Lillo Institute, 

 Tucuman, Argentina, collected January 3, 1949, by Kuschel ; one para- 

 type, U.S.N.M. No. 59364; one paratype in the Museum of Compara- 

 tive Zoology. 



Type locality. — Almacea, Trinidad, Bolivia. 



Remarks. — This species is very close to M. spinipes from Venezuela, 

 having a similar structure, particularly in the spurs on the tibiae. This 

 character is found up to this time in these two species only. The chief 

 difference between the two species appears to be in the proportions of 

 the body, in M. calcariferus the elytra are over twice as long as the 

 thorax in the three females examined although the elytra are scarcely 

 any wider than in M. spinipes. There are also slight differences in 

 the color, the Bolivian species being black, the Venezuelan more fre- 

 quently brownish, and in the punctation on the first segment of the 

 abdomen, which in the Venezuelan species is coarser and denser. 



