48 Mr. H. W. Bates on the Longicorn Coleoptera 
surface clothed with minute silky-green scales, and having a 
well-marked sutural stria with regular rows of black bristles, 
each proceeding from a puncture. Sides of breast rich golden 
green; sternum clothed with hoary tomentum; abdomen red- 
dish testaceous, clothed (especially towards the base) with hoary 
pile. Legs black; thighs beneath hoary. 
3 Apical abdominal. segment much longer than the medial 
segments; ventral plate obtuse at the tip ; ” dor sal plate square, 
with the angles each produced into a stout tooth. 
? Apical abdominal segment of the same relative length as in 
the 3, but the ventral plate more convex ; dorsal plate narrowed 
towards the tip, and terminating in two stout teeth. 
One pair, taken in copuld on a dead branch, at Obydos, on the 
Guiana side of the Lower Amazons. ‘The insect has a deceptive 
resemblance to species of the Cerambycideous genus Chryso- 
prasis, found in the same localities. 
2. Probatius humeralis, Perty. 
Acanthocinus humeralis, Perty, Delectus Anim. Art. Itin. Spix & Martius, 
p. 91, pl. 18. fig. 8. 
P. oblongus, fusco-niger, sericeus: thoracis vitta centrali, scutello, 
macula elytrorum utrinque humerum circumdante lineaque abbre- 
viata marginali aurantiacis. Long. 43 lin. ¢ Q. 
The apical abdominal segment is of nearly the same shape 
in both sexes as in P. Chryseis ; but the ventral plate in the 2 is 
briefly notched at the apex. 
This species has a wide range. I have specimens before me 
from Rio Janeiro, the Upper Amazons, and Cayenne. It is also 
found in Mexico, but exists there under the form of a well- 
marked local variety or race, the P. meaicanus of Thomson (Classif. 
des Céramb. p.17). This differs from the South-American form 
by the orange-coloured marginal streak extending to the tip of 
the elytra, instead of halting halfway, and by the thoracic vitta 
extending over the crown of the head. 
3. Probatius partitus, White. 
P. ellipticus : capite, thorace (brunneo indistincte bivittato) articulo- 
que basali antennarum testaceo-ochraceis: elytris postice valde 
attenuatis, nigris, nitidis, basi obscure testaceis, maculis minutis 
grisels in fasciis undulatis tribus dispositis, nigro setosis, striato- 
punctatis, postice unicarinatis. Long. 4—4# lin. 
The apical abdominal segment is of a similar form in both 
sexes to that of P. Chryseis. The antenne, excepting the pale 
basal joint, are black, with the bases of the joints whitish. The 
thoracic spines are thick, conical, and obtuse. The apical spines 
