of the Amazon Valley. oi 399 
brown colour, one covering the shoulder and extending in a 
short streak to the disk, the other placed obliquely a little be- 
hind the middle; the apex of each elytron is produced into a 
spine. Body beneath thickly clothed with ashy-brown pile; 
the middle of the abdomen shining black. Legs thinly covered 
with ashy-brown pubescence. 
One example, taken at Oyaya, banks of the Curud, below 
Santarem. 
The species is nearly allied to St. melanogenys, but differs in 
the shape and position of the spines beneath the third antennal 
joint, in its clothing and markings, and in the apex of the elytra 
not being squarely truncated with a spine at the external angles, 
but produced on each elytron into a stout spine. 
4. Stetrastoma ethiops, nu. sp. 
St. modice elongatum, depressum, supra tomento atro-griseo vesti- 
tum: capitis thoracisque lateribus et plagis magnis duabus ely- 
trorum nigris : elytris apice valde spinosis. Long. 8-10 lin. ¢ 9. 
Head and labrum clothed with very dark-grey pile, the former 
with three longitudinal raised lines on the front, the central one 
extending to the nuchus, the lateral ones short and very promi- 
nent ; sides black. Antennz black; bases of the joints greyish, 
the third with a few very fine spines or bristles beneath, placed 
wide apart; the basal joint in the ¢ pyriform-clavate, smooth. 
Thorax quadrituberculate on each side, the lateral prominence 
very large, trituberculate, the tubercle near the fore angle pro- 
minent; the dorsal surface depressed, punctured, tricarinate ; 
the central keel very faint, the lateral ones strongly pronounced ; 
thickly clothed with very dark-grey pile, the sides each with a 
black stripe between the lateral keel and the tubercles. Elytra 
depressed, elongate, subtrigonal; the centro-basal ridges pro- 
longed behind to the apex, strongly curved outwards, and granu- 
lated to two-thirds the length, then flexuous and smooth to their 
termination ; the surface faintly and sparingly granulate-punc- 
tate, with a few large granulations, besides, on the shoulders; 
very dark grey, the sides having each two large, irregular, black 
patches—one, which is sometimes broken into smaller spots, 
covering the shoulder and extending in a slender streak to the 
disk, the other placed obliquely a little behind the middle; the 
tips of the elytra are briefly sinuate-truncate, the external 
angles produced into stout spines. Body beneath and legs 
clothed with very dark-grey pile; the middle of the abdomen 
naked, shining black. The fore tibie of the ¢ are untoothed. 
This species occurred only at Ega and St. Paulo, on the Upper 
Amazons. It differs very little, except in colour, from St. cwno- 
sum, and may be considered a geographical variety or race of 
