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Buprestides and Elaters without the aid of Herbst's figures and 

 descriptions, which include numbers of them. Tlie name of 

 Omalisus coccinatus Say, was given me by that gentleman, but 

 is has not yet been published by him. In the specimen of your 

 807 sent me and marked 3, 4, 4, I discovered, by the use of a 

 lens surrounded by a concave reflector, that it was tetramerous. 

 Still my specimen may exhibit that conformation, while yours 

 of the other sex may have the hand trimerous. I consider it 

 to belong to the genus Mycetopliagus (vid. 31. hicolor and 

 31. flavijjes Fabr.), of which I have no other examples than the 

 species you have sent me. Yon mistook the drift of my remark 

 on your 814. It was intended to remind you that in Elodes 

 the labial palpi were forked. Having only a single specimen, 

 I was loth to sacriiice it by dissection, and have no other insect 

 allied to it. Your Rhipisera (for such I consider it) must be 

 a charming insect, and I hope you will find the male, with its 

 antenna? of thirty-five joints. It diflPers from the Ptilinus 

 inystacinus^ as figured by Drury, and is very distinct from 

 marginata Kirby. Latreille says (Nonv. Diet. dTIist. Nat., 

 Vol. XXVIII, article Ptyocerus) that ^^ 31elasi8 2n(^ea of Pal. de 

 Beauvois is congeneric with 31. mystaciinis^ the type of La- 

 treille's genus Rhlpicera and Thunberg's Ptyocerus.''' I have 

 therefore extracted the description of tlie 31. j9/c?ea from 

 Beauvois's splendid Avork, and annex a sketch of his insect, 

 which cannot be confounded with yours. 



Your having incidentally mentioned Platycerus securidens., 

 reminds me that if I marked your insect of that name, it Avas 

 probably an error. I never saw the true P. securidens Say, 

 till about a year since, when I received one from j\Ir. Leonard, 

 which agreed in size, etc., with Say's description. The mandi- 

 bles are very dift'erent from those of the other and larger 

 species, which I had hitherto supposed to be P. securidens. 

 This larger species appears to be the lAicanus (^Platycerus^ 

 piceus of Weber. Weber describes another North American 



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