41 
• broadened anteriorly than in any species of Acanthoderes, and 
the fore angles are more strongly pronounced. The mandibles 
are long, very slightly bowed, and much flattened. The centro- 
basal ridges of the elytra are curved outwards and prolonged 
behind as more or less flexuous smooth keels to the apex. In 
the males of some speeies the basal joint of the antennae forms 
an irregular many-angled club, and is longer in proportion to 
the third than is the rule in the section to which the genus 
belongs. 
1. Steirastoma depressum, Fabr. 
Ceramhyx depressus, Fabr. Ent. Syst. i. ii. 260. 32. 
St. breve, depressum, postice valde attenuatum, nigrum, tenuiter 
griseo tomentosum : thoracis lateribus quinquetuberculatis, dorso 
depress© tricarinato : elytris subtrigonis, carinis centro-basalibus 
vaide curvatis ramulum suturam versus emittentibus, apice spi- 
nosis : pedibus nigris, cinereo obscure variegatis : corpore subtus 
nigro, nitido, lateribus ochraceo tomentosis. Long. 7-1 1 lin. ^ $ . 
Head blaek, scantily clothed with grey tomentum, sparingly 
punctured with three raised longitudinal lines, the lateral ones 
flexuous, the central one straight and running from the vertex 
to the edge of the epistome. Antennse half as long again as the 
body in the c^, a little longer than the body in the $ , black, the 
bases of the joints ashy; the first joint in thecjof an irregular 
clavate shape, rugose, tubereulated at the apex. Thorax puiie- 
tured near the fore and hind margins ; the sides have each five 
tubercles, two anteriorly and three on the moderately produced 
lateral prominence ; the dorsal carinae are smooth, and shining 
black, the lateral ones being flexuous, interrupted, and tubercu- 
late. The elytra are clothed with thin ashy tomentum, streaked 
and spotted with blaek ; the centro-basal ridges are granulated 
and strongly curved, the posterior end of the curve emitting a 
short branch towards the suture; afterwards each is continued 
as a flexuous and smooth keel to the apex : the apex itself is 
produced into a strong tooth or spine, which varies in length in 
diflferent individuals. The fore legs of the S ai’e much elon- 
gated. 
This is a common Guiana species, and is generally distri- 
buted throughout the Amazon region, being found everywhere 
in new clearings, sometimes under the loose bark of trees. Like 
all the other species of the genus, it is sluggish in its motions, 
and feigns death when touehed, bending its legs in a rigid posi- 
tion, and falling to the ground. As the Fabrician description is 
insuflicient, and his name has been referred to a nearly allied 
but distinct South Brazilian species, I have thought it necessary 
to give a lengthened diagnosis. According to the British Museum 
