56 
middle is a broad irregular dark-brown belt, preceded by a yel- 
low line ; the dark-brown colour runs from the belt along the 
margins and suture to the apex. The body beneath and legs 
are clothed with greenish-yellow pile, which is denser on the 
sides of the breast and on the tarsi. The fore tibise are dilated 
and compressed. 
One example, taken on the trunk of a tree at Tunantins, on 
the Upper Amazons. This and the following have a most de- 
ceptive resemblance to species of Curculionidse of the genus 
CratosomuSj which occur in numbers on the trunks of certain 
trees. The general colour is exactly the same, and the resem- 
blance is made more perfect by the large, glossy, basal tubercles 
of the elytra, which are merely modifications of the ordinary 
centro- basal ridges existing in this section of the Lamiaires. 
The shortness and slenderness of the antennae, rendering the 
organs almost invisible at a short distance, also assist in perfect- 
ing the disguise, which completely deceived me when I saw the 
insect in situ, G. scabripennis (Serville), a native of Cayenne, 
belongs to this same group, all the forms of which appear to be 
excessively rare. 
4. Gymnocerus crassus, n. sp. 
G. ovalis, convexus, tomentosus ; thorace elytrisque fulvis, his fascia 
latissima et macula subapicali canis. Long. lin. $ . 
This species very much resembles the preceding, and might 
be treated as a variety of it, although it seems more convenient 
to deal with it as a separate form. The punctures of the elytra, 
with their granulations, are much more strongly developed; 
otherwise the only differences observable are those of colour. 
The head is greenish yellow, with the crown and occiput grey. 
The thorax does not differ from that of G. cratosomdides. The 
base of the elytra is occupied by a narrow belt of a fulvous co- 
lour, and a much broader belt of the same hue crosses the elytra 
behind the middle ; the rest of the surface is hoary grey, with 
the exception of the margins and suture near the apex, which 
are blackish. 
I found one individual only of this form at Ega, on the trunk 
of a tree. 
5. Gymnocerus monachinuSy White. 
Anisocerus monachinus. White, Cat. Long. Col. in Brit. Mus. ii. p. 406, 
pi. 10. f. 3. 
This magnificent species varies in size from 7^ to 11 lines. 
The fourth antennal joint is gradually and slightly dilated at the 
apex, the third is simple. The ground-colour of the upper sur- 
face in the S is chalky white, in the 2 rose-red, the latter being 
very bright during life. I found the species only within a radius 
