54 Mr. Wcstwood on the Genus Ctenostotna. 



the penultimate joint of the anterior, as well as of one of the intermediate, 

 and of one of the posterior, tarsi, as bilobed. This joint, however, iu 

 all the legs is simple in both sexes of Ct. ichneumoneum; and also, I 

 imagine, in all the other species, else Dejean would doubtless have noticed it. 



The elytra of the male are elongated and rounded at the tips, whilst 

 those of the female are less elongated, and truncated so as nearly to form 

 three slight teeth. This character therefore, in this species at least, is a 

 sexual and not a specific one. 



The penultimate segment of the abdomen of the male is emarginated 

 beneath; the last segment in the females is long and pointed at the tip, 

 and there are two lateral lobes above, united apparently on their inner 

 surface. 



With reference to the geographical distribution of insects, it may be 

 mentioned that the genus Ctenostoma appears to represent in South 

 America (of which all the species are natives) the Asiatic genus ColHuris. 



I am happy in having come to the possession of the sexes of one of 

 the species of this rare and interesting genus, and in being consequently 

 enabled to illustrate it with the sexual characters given above, and to 

 correct the specific characters of the same species given by Dejean. 

 Ct. ichneumoneum. Dej., Species General, &c. v. 2. Suppl. p. 436. $ 



, Guerin, Iconogr. du Regne Animal, Insectes. pi. 3. 



fig. 3. 



Ct. nigro-subaeneum, nitidum, elytris punctatis basi subtransversim rugosis, 



macula media transversa apiceque flavis. 



Long. Corp. ,J et $ , lin. 5J. 



Habitat in Brasilia. In Mus. Dejean, nostr. ^ et $ . 



This is a very distinct species. The sexes are of equal size, and their 

 general specific characters are precisely similar, except as before and 

 after mentioned. The antennae are brownish black, with the first three 

 joints yellowish brown, their upper surface being black. The surface of 

 the head is nearly flat in front, and punctured, especially between and 

 behind the eyes, and has upon its surface several rugosities forming two 

 longitudinal cbarmels between the eyes, and terminating behind them 

 in a semicircular transverse ridge, behind which the head is narrower, 

 smooth, and shining. The colour of the head, trophi and thorax is 

 shining black, slightly bronzed ; the latter is highly pohshed and impunc 

 tate, and formed as in Ct. trinotatum, as described by Dejean; the elytra 



