187 
Genus Oncideres, Serville. 
Serville, Ann. Soc. Ent. Fr. (1835) iv. 
The chief characters of this, the typical genus of the group, 
are furnished by the elongate-oblong or cylindrical form of body; 
the broad head and convex occiput, with consequent wide sepa- 
ration of the antennse at their bases ; the elongated eyes ; the 
clavate shape of the basal antennal joint, and straight form of 
the third joint; the short transverse thorax; and, lastly, the 
great length of the claw-joint of the tarsi, which exceeds that of 
the three remaining joints taken together. 
The species are all found on the branches of trees, which they 
amputate from the living tree by gnawing deeply into the bark 
and wood, making a ring-like incision, until the bough breaks 
off by its own weight. I have often seen boughs thus severed 
from green and living Caju trees, and hence discovered that the 
best means of finding the insects was by examining the ampu- 
tated portions lying on the ground in woods or the thinner parts 
of the forest. The object of the severance is apparently to 
create a supply of dead wood in which to deposit their eggs and 
rear the larvae. 
1. Oncideres Callidryas, n. sp. 
O. minus convexus ; thorace griseo-tomentoso ; elytris basi minute 
granulatis, medio confertim punctatis, nigris, guttis numerosis- 
simis carneo-griseis. Long. 10| lin. <S $ . 
Head much narrower than the middle part of the thorax, 
clothed with pinkish-tawny pile ; forehead plane, punctured ; 
antenniferous tubercles ( <^ ) on each side armed with longish 
acute teeth directed forwards ; eyes oblong. Antennae about the 
same length as the body in the female, twice the length in the 
male, black. Thorax with transverse depressions, sides each 
armed with a strong conical tubercle, clothed with hoary- grey 
pile. Scutellurn and basal margin of elytra hoary grey. Elytra 
less cylindrical and convex than in the more typical species ; 
shoulders prominent and surmounted by a retrocurved tubercle, 
base and shoulders thickly and finely granulated, middle part 
simply but thickly punctured, punctures becoming finer poste- 
riorly, and disappearing before the apex ; colour black, sprinkled 
throughout with small grey or pinkish-grey spots, some very 
minute, others larger ; near the middle of each side the spots 
are whiter, and tend to aggregation. Body beneath hoary 
white. Legs black, thinly clothed with grey pile. 
Para, banks of the Tapajos, and Ega ; one pair taken in co- 
pula on a branch of a felled tree at Para. The elytra are much 
more thickly spotted in the Ega examples than in those from 
Para and the Lower Amazons. 
