510 SEREICOKNIA. 



horizontal, V-shaped ; metasternum broad between the middle coxae, gradually raised forwards to meet 

 the protuberant mesosternum, concave along the median line. 

 Length 29, breadth 7f millim. ( $ .) 



Hab. Mexico, Amula in Guerrero 6000 feet (H. H. Smith). 



One example only of this interesting novelty has been received. Allied to 

 0. corvinus, but differing from it in the almost glabrous, highly polished, and 

 flattened upper surface, the very sparse, minute punctuation, the longer thorax, and 

 the greatly developed mesosternum. In this last-mentioned character it differs from 

 all the other species of the genus. 0. glabratus somewhat resembles the North- 

 American Melanactes piceus, De Geer, but differs from that insect in having double, 

 widely separated prosternal sutures, strongly triangularly dilated posterior coxal plates, 

 &c, as well as in its much more elongate shape. 



5. Orthostethus cavifrons. (Tab. XXII. fig. 14, e .) 



Elongate, robust, moderately shining : obscure brownish-castaneous, the prothorax with a large indeterminate 

 patch on the disc, widening anteriorly, piceous or pitchy-black ; above and beneath thickly clothed with 

 short, decumbent, f ulvo-cinereous hairs. Head very broadly excavate along the middle (the sides of the 

 front appearing raised), coarsely, closely punctate, the eyes very large ; antennas about reaching the hind 

 angles of the prothorax in the male, shorter in the female, the joints from the fourth dilated and strongly 

 serrate, 3 slightly shorter than 4. Prothorax a little longer than broad, with the sides subparallel or very 

 gradually converging in their median third, rounded in front, and feebly sinuate behind ; the hind angles 

 very long and strongly divergent, slightly incurved at the tip, and finely carinate ; the surface thickly, 

 coarsely punctate, the punctuation becoming coarser, denser, and umbilicate at the sides in front, and 

 sparser along the middle of the disc, down the centre of which is an indistinct smooth line. Elytra three 

 times the length of the prothorax, rapidly narrowing from a little below the base, attenuate at the apex, 

 the sutural angles sharply mucronate ; closely, finely, rugulosely punctate, and with iudications of faint, 

 longitudinal furrows. Beneath closely and finely, the prosternum coarsely and sparsely, punctured ; 

 mesosternum raised, horizontal, V-shaped. 



Length 23|-28, breadth 6£-7| millim. ( <$ $ .) 



Hab. Panama, Volcan de Chiriqui 2000 to 3000 feet (Champion). 



Seven examples. Closely allied to O. infuscatus, but differing from that insect in 

 the broadly excavate front in both sexes ; it is of the size of the smallest specimens of 

 that species. The frontal excavation is very broad, and extends backwards to the 

 vertex. 



6. Orthostethus pectinicornis. (Tab. XXII. figg. 16, 6 ; 16 a, antenna.) 



d" . Very elongate, broad, shining ; black, the elytra brownish-black, the under surface pitchy-brown ; some- 

 what thickly clothed with short, fine, yellowish -cinereous pubescence. Head "closely, coarsely punctate, 

 broadly excavate in front ; antennae extending to far beyond the hind angles of the prothorax, joints 

 2 and 3 very short, subequal, 4 about three times the length of 3, 4-11 pectinate. Prothorax convex, 

 nearly as long as broad, trapezoidal, the sides a little rounded in front ; the hind angles long, incurved at 

 the tip, sharply carinate ; the surface closely, coarsely punctate, the punctuation more scattered on the 

 disc, down the median third of which is a smooth space. Elytra about three and one-fifth times the 

 length of the prothorax, and distinctly wider than it, gradually narrowing from the middle, and conjointly 

 rounded at the apex, the sutural angles sharp ; closely, confusedly punctate, without trace of striae. 



