Mr. Westwood on the Genus Ctenostoma. DD 
are long, very narrow at the base, and increasing nearly to the tip. 
Dejean says of the elytra of his insect, “leur extrémité est échancrée et 
‘< n’est pas prolongée,”’ 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. “ Trouvée’’ according to Dejean “< dans les environs 
«© de Rio Janeiro, dans un bois trés-touffu. Elle se tient sur les branches des 
* arbres et court avec beaucoup d’agilité.’’ The species differs from Ct. 
formicarium, Colliuris 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. bifasciatum, elytris posticé levigatis, fascia anticd medidque 
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, pl. 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- 
leoptéres 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 asa 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, 
