Mr. Westwood on the Genus Ctenostoma. 55 



are long, very narrow at the base, and increasing nearly to the tip. 

 Dejean says of the elytra of his insect, " leur extrcmite est echancrce et 

 " n'est pas prolongee," evidently from an inspection of the female. The 

 variation in the formation of the elytra of the sexes I have detailed 

 above. They are of the same colour as the head, and covered with punc- 

 tures, especially at the base, where these occasionally unite together and 

 form a few transverse ridges. These have one transverse, pale yellow 

 fascia behind the centre, slightly interrupted at the suture, and the apex is 

 of a more obscure yellow colour ; the slender margin of the elytra is pale 

 brown. The legs are black bronzed, with the base of the four posterior 

 femora pale yellowish brown. All the parts of the body have long 

 delicate hairs scattered sparingly over them. 



The sexes of this species now in my collection were the only two 

 individuals contained in a large collection of Brazilian insects lately 

 arrived in England. " Trouvee" according to Dejean " dans les environs 

 " de Rio Janeiro, dans un bois tres-touffu. EUe se tient sur les branches des 

 " arbres et court avec beaucoup d'agllite." The species differs from Ct. 

 formicarium, CoUiuris formicarium. Fab., in having the apex of the 

 elytra pale ; and from Ct. trinotatum in wanting the pale spot at the base 

 of the elytra. Its situation in the genus may be seen by the following 



Synopsis Specierum. 



1. Ct. formicarium, elytris macula media transversa flava. 



2. Ct. ichneumoneum, elytris macula media transversa apiceque flavis. 



3. Ct. bifasciatuin, elytris postic^ leevigatis, fascia antica mediaque 

 transversa flavis.* 



4. Ct. trinotatum, elytris macula baseos, mediaque transversa apice- 

 que flavis. 



* This new species of M. Dejean (Icon, des Col. d'Eur., 2d Edit., Vol. I. p. 

 55, pi. 6, f. 5.) might, from the coloured figures, be regarded as the insect 

 figured under the name of C. formicarium in the first edition of the Co- 

 leopteres d'Europe (there being, as I have observed below, some doubt as to 

 the identity of that species and the insect described by the German and Russian 

 entomologists under the name of trinototum). As, however, Dejean himself 

 gives this as a new species, without any reference to former figures and descrip- 

 tions, it must doubtless be considered as distinct, and the above question still 

 remains unsettled. 



