2 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



in the above-mentioned article, he assigned the species of Myochrous 

 described by Blanchard and Philippi, separating them from Myo- 

 chrous because they are wingless, have the elytra soldered together at 

 the suture, and are more gibbous and covered by tubercles. In the same 

 year Baly ^ described three new species of Myochrous — M. armatus 

 from Brazil, M. explanatus from Venezuela, and M. sdllei from Mex- 

 ico. Of the remaining species in the genus, two North American ones 

 have been described by LeConte, five have been described in the Bi- 

 ologia Centrali-Americana by Jacoby, and one from Argentina by 

 Brethes. Kecently Schaeffer has described three and Johnson one 

 from the United States. 



In 1947 ^ I worked up the West Indian material in the Museum of 

 Comparative Zoology and the National Museum collections, and in 

 my study of these species I came to realize that the United States 

 species were somewhat confused, particularly those closely related to 

 the important economic species M. denticollis ( Say) . A Mexican spe- 

 cies that invades southern Texas and New Mexico and a southeastern 

 species have both gone under that name. In the squamosus group, 

 furthermore, there were two other unrecognized species, and in Cali- 

 fornia occurs another closely related to M. longulus. As for the Mex- 

 ican and Central American species, nothing has been done since 

 Jacoby's treatment of them in the Biologia. Many specimens of Myo- 

 chrous, which are impossible to name because they are mostly unde- 

 scribed species, are constantly being intercepted at ports of entry in 

 shipments of fruit and vegetables. In studying the Central American 

 species I included some South American ones, as some were common to 

 both Central and South America. Since only five species have been 

 described from South America, and since others were represented 

 in both the Museum of Comparative Zoology and the National Museum 

 collections, I have been tempted to describe the most distinct and 

 well-marked species. Others, of which we have not sufficient material 

 to warrant drawing up a description, I have left untouched. Un- 

 doubtedly many additional species exist throughout Central and South 

 America that will turn up in future collections. 



The genus is a difficult one because the species are so closely related. 

 They are all similar in color, dark reddish brown or piceous black, 

 and all are more or less densely covered by pale scales that hide the 

 underlying sculpture, particularly that of the thorax wherein most 

 of the differences appear. The genitalia, for the most part, are of the 

 same general shape and in many, without close examination, seem 

 much alike. In addition, there is considerable overlapping in the 

 range. But after studying the material from both North and South 



* Trans. Ent. Soc. London, ser. 8, vol. 2, pt. 4, p. 335, 1865. 

 » Blake, Proc. Ent. Soc. Washington, vol. 49, pp. 22-28, 1947. 



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