DIASTETHUS.—RHIANOPSIS. 239 
punctures on the meso- and metapleura coarse; prosternal sulcus narrow, the coxs narrowly separated ; 
ventral segment 1 excavate down the middle in the ¢. Femora denticulate and also armed with one or 
two longer acute teeth. Tarsal joint 2 much narrower than 3. 
Length 343-4, breadth 24-23 millim. (d 2.) 
Hab. Mexico, Toxpam and Yolos (Sallé), Oaxaca (Hoge). 
Four specimens. A small species, with short, broad prothorax, and sharply striate, 
red elytra, the latter sometimes black at the base and apex. ‘The strie are broader 
than in D. humerosus and the second tarsal joint is relatively narrower. ‘The 
mandibles have a sharp tooth on the outer edge beneath. The teeth on the anterior 
femora are shorter than those on the other two pairs. The following two forms are 
closely related to D. rufipennis, but they cannot be satisfactorily included under that 
species, 
24, Diastethus pallidipennis, sp. n. 
Very like D. rufipennis, but with the antenne, tip of the rostrum, tarsi, and apices of the tibi ferruginous, 
. and the elytra testaceous ; the strie of the elytra deeper, with coarse seriate punctures showing through 
from beneath, the interstices convex ; the mandibles with a tooth at the sides beneath. 
Length 34-4, breadth 2} millim. (¢.) 
Hab. Mexico, Yolos in Oaxaca (Sal/é). 
Three males. 
25. Diastethus obliquus, sp.n. (Tab. XIII. figg. 20, 20a, 2.) 
Very like D. rufipennis, but with the antenne, tip of the rostrum, tarsi, apices of the tibie, and a very broad 
oblique stripe on each elytron extending from the shoulder to the suture, ferruginous ; the strie of the 
elytra deep, the interstices flat; the mandibles with a tooth at the sides beneath. 
Length 32, breadth 275 millim. (@.) 
Hab. Mexico (coll. Solari). 
One female, evidently fully mature. 
RHIANOPSIS, gen. nov. 
Mandibles rather long, stout, without tooth on their inner edge, dehiscent at the apex; rostrum stout, curved, 
elongate; prothorax narrow and tubulate in front, deeply bisinuate at the base; scutellum well- 
developed, free, transverse; pygidium not visible; prosternum broadly sulcate, unarmed; mesosternum 
depressed; all the cox very widely separated ; femora subclavate, almost smooth, sharply unidentate, 
without trace of sulcus beneath, except at the apex; tibie strongly unguiculate at the apex; tarsi 
rather narrow, the claws long and divergent ; body elliptic, polished, glabrous above, 
Type, BR. ferrugineus. 
This genus is based on a single species from Panama which is nearly related 
to Rhianus and Diastethus. The very widely-separated anterior coxe, the rather 
long, unemarginate, dehiscent mandibles, the non-sulcate, unidentate, almost smooth, 
clavate femora, the broadly sulcate, unarmed prosternum, the long, divergent tarsal 
claws, and the elliptic general shape are its chief characters. 
2HH2 
