BEETLES OF THE GENUS MYOCHROUS — BLAKE 53 



shiny. Elytra over twice as long as prothorax and a little wider, 

 moderately convex with small humeri and a short intrahumeral de- 

 pression and little trace of basal callosities; punctation coarse, dense, 

 and in basal half sometimes a little confused, otherwise striately punc- 

 tate; two fairly well marked costae; scales short, closely appressed, 

 moderately wide and presenting a somewhat mottled appearance, al- 

 most concealing the sculpture beneath. Body beneath less densely and 

 coarsely pubescent, abdominal segments closely punctate. Length 

 6.6 to 6.9 mm. ; width 3 mm. 



Tyfe and jmratype. — Type female in Institute Miguel Lillo, Tucu- 

 man, Argentina, collected December 3, 1948, by F. Monros ; paratype, 

 a male, U.S.N.M. No. 59225, collected at Ledesma, Jujuy Province, 

 Argentina, December 1, 1948, by F. Monros. 



Type locality. — Lombreras, Salta Province, Argentina. 



Remarks. — This species is closely related to M. stenomorphus and 

 the pair is strikingly unlike any other species from South America. 

 M. TTioQirosi resembles M. stenomorphus in being of the same reddish- 

 brown coloration and in having a similar convex, straight-sided pro- 

 thorax with tiny teeth. Even the aedeagus is similar although 

 heavier. Unlike M. stenomorplius., this is one of the largest of South 

 American species of BIyochrous., being as large as M. armatus. I take 

 pleasure in naming it after its collector, Ing. Francisco Monros, who 

 has published excellent work on Chrysomelidae. 



MYOCHROUS IMMUNDUS Erichson 

 PiLATE; 5, FiGXraE 1 



Myochrous imtmindus Ekichson, Archiv fiir Naturg., vol. 13, p. 164, 1847. 



About 6 mm. in length, elongate-oblong, black, shining with a bronzy 

 luster beneath the long brown and white hairlike scales, intermingled 

 with shorter, broader, and more appressed scales; prothorax as long 

 as wide with rounded sides having three teeth marked by a tvift of 

 hairs on each, very densely and coarsely punctate. Anterior tibiae 

 without conspicuous inner tooth. 



Head covered with pale pubescence, on occiput fine and not hiding 

 the dense punctation below, in lower front becoming slightly coarser, 

 between the antennal sockets lightly hairy, the usual occipital ridges 

 if present at all very indistinct. Antennae and mouthparts reddish 

 brown, antennae extending a little farther than usual, the third joint 

 longer than fourth. Prothorax fully as long as wide, with rounded 

 sides, not very convex, the three lateral teeth accentuated by a tuft 

 of hairlike scales; a slight transverse depression anteriorly and a 

 deeper one along the basal margin ; punctures coarse and very dense, 

 particularly toward the base ; pubescence dense, the longer scales not 

 closely appressed and somewhat concealing the shorter broader ones 



