of the Amazons Valley. 175 



Genus Oncideres, Serville. 

 Serville, Ann. Soc. Eut. 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 antennae 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 Cajii 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. 6"$. 



Head much narrower than the middle part of the thorax, 

 clothed with pinkish-tawny pile; forehead plane, punctured; 

 antenniferous tubercles ( J* ) 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. Scutellum 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- 

 puld 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 Lovyer Amazons. 



