2i6 Memoirs of the Indian Museum. [Vol. Ill, 



angles of head each of about 120°; canthus rounded at its extremity. Pronotum 

 with a fine marginal groove on each side which does not extend upwards much beyond 

 the angles either before or behind ; median groove obsolete or absent ; scars usually 

 small, almost or entirely unpunctured, other depressions sometimes present above, both 

 in front of, and behind them. Lateral pia'es of under side of prothorax as in 

 preceding species. Mesotliorax polished above, but dull below; scutellum smooth; 

 episternum with normal oblique band of punctures. Mesosternum with or without 

 very indistinct .scars. Metasternnm with central area distinct, vaguely grooved in 

 the middle line, more or less distinctly in contact with smooth, strongly defined, 

 oblique ridges bounding lateral areas ; lateral and anterior intermediate areas rugosely 

 punctured and hairy; posterior intermediate areas polished, more or less scarred 

 by large punctures in places especially on the inner side in front Posterior margin 

 of hind coxae finely, often indistinctly, punctured and hairy. Second abdominal 

 sternum irregularly marked with indistinct coarse punctures; succeeding sterna 

 smooth. Elytra flattened above, hairless; lateral grooves much wider than ridges 

 between them, their regularly arranged punctures drawn out into transverse furrows; 

 dorsal grooves normal, two or three innermost on each side unpunctured at least 

 in front. 



riberioides austeni, n. sp. 

 PI. xi, figs. 15-15(7. 



Regd. No. '^' '^ {type) Dafla Expedition H. H. Godwin-Austen. 



"^ Dikranc; Valley ' H.H.Godwin-Austen. 



'"i't' Kalek, Abor Country, 3S00 ft. , 29-xii-ii S. VV. Kemp. 



Description. — Length 41-47 mm. This species differs from the last in the follow- 

 ing characters only. Antennae more massive. Upper tooth of mandibles more 

 strongly developed, especially that of the left side. Mentum with anterior margin of 

 median area evenly convex or a little prominent' (never excavate) in the middle, 

 extreme anterior angles of lateral areas smooth and unpunctured. Head with inner 

 tubercles larger and thicker and directed more definitely forwards; ridge joining 

 them to outer turbercles also stouter, not forming so continuous a curve with ridge 

 joining them to one another ; distal margin of outer tubercles of Abor specimens slightly 

 convex as seen from side instead of concave. Punctures of mesothoracic episternum 

 extending further into upper front angle as in Pleurarius brachyphylltis ; mesosternum 

 with very distinct scars which are broad in front and taper out behind. Hind coxae 

 unpunctured; second abdominal sternum somewhat smoother; elytra with grooves 

 uniformly narrow and punctured both above and at the sides. 



Habits. — Mr. Kemp informs me that the two specimens of this species that he 



' This label bears also the word " Nanang's." 



* This prominence may be indistinctly marked off by a vague groove behind (No. "-^'f shows this best 

 among our specimens) and such specimens form a natural transition to the aberrant " Chilomaziis" 

 borcalis. Arrow (1907, pp. 467-8), from the Naga Hills. 



