DIASTETHUS. 251 
Three specimens, one of which is immature. This is one of three species labelled 
with the MS. name Centrinus erythroderes, Chevr., in the Sallé collection. It may be 
recognized at once from the other forms with a red prothorax by the laterally sulcate 
rostrum (the groove being continued forward to near the tip), the long, stout, antennal 
club (as long as in some of the species of Cylindrocerus), and the unidentate anterior 
femora. 
15. Diastethus aztecus, sp.n. (Tab. XIII. figg. 12, 12@, ¢.) 
Subrhomboidal, shining, black, the prothorax sometimes reddish, glabrous above, the scattered punctures of 
the under surface each bearing a minute hair-like scale. Prothorax strongly rounded at the sides from 
near the base to the narrow, tubulate, anterior portion, smooth, very convex or almost gibbous on 
the disc. Scutellum transverse. Elytra depressed below the prominent basal margin, the sutural stria 
and those along the lower margin deep, the other striz faint, the interstices smooth and flat, the basal 
lobe rounded, the humeri rounded and rather prominent. Prosternal sulcus deep. Femora each with 
two small teeth, the anterior pair sometimes with a single distinct tooth and two or three small 
denticles. 
¢. Prosternum armed with two spines of variable length, sometimes with a deep circular excavation between 
them ; first ventral segment broadly flattened down the middle. 
Length 33-6, breadth 23-32 millim. (¢ @.-) 
Hab. Mexico, Acapulco (Hége), Oaxaca (Mus. Brit., Hoge), San Andres Tustla, 
Toxpam, Panistlahuaca, Tehuantepec (Sadlé), Atoyac, Vera Cruz (H. H. Smith), 
Temax in N. Yucatan (Gawmer); Guatemaa, Panzos (Champion); Panama, Caldera 
in Chiriqui (Champion). 
One of many similar shining black forms, and distinguishable by the very convex 
disc of the prothorax, the faintly striate disc of the elytra (the sutural and marginal 
striz alone deeply impressed), and the almost glabrous, sparsely punctate under 
surface. ‘he prosternal spines of the male vary greatly in length, and in most of the 
well-developed specimens the broadly sulcate prosternum has a very deep circular 
excavation between them. ‘The three specimens from Chiriqui are very small, and 
two of them have the prothorax rufescent. 
16. Diastethus gracilirostris, sp.n. (Tab. XIII. fig. 13, ¢.) 
Subrhomboidal, shining, fusco-castaneous, the rostrum and antenne obscure ferruginous; glabrous above and 
beneath. Rostrum very long and slender, thickened at the base and widened at the apex, strongly 
arcuate, the basal portion only punctate, the antenne inserted at about the basal fourth, joints 1 and 2 
of the funiculus elongate, equal in length, 3-7 short, the club rather long, acuminate-ovate. Prothorax 
broad, convex, somewhat gibbous on the disc, the sides arcuately converging from the base, abruptly 
constricted in front, the base obliquely depressed on each side of the median lobe ; sparsely punctate, the 
punctures becoming much coarser towards the sides. Scutellum transverse. LElytra triangular, slightly 
depressed below the basal margin and along the suture anteriorly, the disc also with a faint transverse 
depression extending across the interstices 3 and 4 before the middle; deeply striate, the strie faintly 
punctate, the interstices smooth and flat, Beneath rather sparsely punctate, the punctures on the pro-, 
meso-, and metapleura very coarse. Prosternum with the anterior portion long and declivous, slightly 
depressed down the middle, and with a minute tubercle in front of each coxa, the coxe widely separated. 
Ventral segment 1 flattened and alutaceous in the middle and here connate with 2. Femora clavate and 
