102 
minal dorsal plate truncate and bidentate in both sexes; corre- 
sponding ventral plate obtuse, and, in the females, slightly- 
notched. Elytra setose, even, briefly truncated and generally 
spined at the apex. Legs moderate ; thighs clavate ; tarsi short ; 
basal joint of the hind foot about as long as the two following 
taken together. 
This is one of the best defined and most homogeneous genera 
in the host of variable forms constituting the group Leiopodinse. 
The character drawn from the apical abdominal segment is 
seen to be constant here, bringing together species agreeing 
in facies and many other points, but greatly diversified in colours 
and markings. 
1. Probatius Chryseis, n. sp. 
P. ellipticus : capite thoraceque auratis ; elytris viridibus sericeis, 
nigro setosis, apice mucronatis ; abdomine testaceo-rufo. Long. 
5-6 lin. 2 • 
Head and thorax shagreened, of a rich golden colour shading 
into green with the play of light, naked. Antennae black, setose; 
thoracic spines large, acute, pointing obliquely rearwards, and 
placed very near to the hind angles. Elytra of a breadth nearly 
equal to three-fourths their length, thence narrowing to the 
apex, which, in each elytron, is prolonged into an acute spine ; 
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. 
c? Apical abdominal segment much longer than the medial 
segments ; ventral plate obtuse at the tip ; dorsal plate square, 
with the angles each produced into a stout tooth. 
? Apical abdominal segment of the same relative length as in 
the c5' , but the ventral plate more convex ; dorsal plate narrowed 
towards the tip, and terminating in two stout teeth. 
One pair, taken in copula 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^ 
prasiSf found in the same localities. 
2. Pi'obatius humeralis^ Perty. 
Acanthocinus humeralis, Perty, Delectus Anim, Art. Itin. Spix & Martius, 
p. 91, pi. 18. fig. 8. 
P. oblongus, fusco-niger, sericeus : thoracis vitta centrali, scutello, 
macula elytrorum utrinque humerum circumdante lineaque abbre- 
viata marginali aurantiacis. Long. 4^ lin. cf $ . 
The a’pical abdominal segment is of nearly the same shape 
