2o8 Memoirs of the Indian Museum. [\'oi.. Ill, 



fig. 2'. The form of the anterior parts of the margmal groove of the pronofum 

 and the puncturing of the ahdomiiud slriiui are both extremely variable. 



Genus TAENIOCERUS, Kaup. 

 Taeniocerus bicanthatus (Percheron). 

 PI. xi, figs. 7-7/;. 

 Regd. No. -*-' ? J- Wood- Mason. 



9177 MBi-S «38S 



Johore, Malay Peninsula 



No. ""' is markedly smaller than any of the others, but in structure it agrees with 

 them perfectly. In all the specimens I have seen the external angle of the canthus 

 is more or less obtuse, scarcely rectangular as it is shown in Percheron's figure, and 

 certainly not acute as in Kaup's figure. 



Description. — Length 24-29 mm. Labrum about twice as broad as long ; anterior 

 angles rounded, laterally prominent; anterior margin concave. Upper tooth of 

 mandibles somewhat obtuse and not very prominent ; uppermost terminal tooth 

 obsolete; anterior lower tooth of left mandible wider than that of right ; the former, 

 and often the latter also, more or less bifid, the upper denticle being longer than the 

 lower. Mentum with a considerable angular prominence in middle of anterior 

 margin; this prominence continued backwards to posterior margin as a hairless, and 

 usually smooth and more or less hollowed, triangular area ; lateral portions of 

 mentum flattened, hairy and coarsely punctured. Head smooth and polished as a 

 whole, but punctured behind supra-orbital ridge, beside central tubercle, and 

 in area enclosed by the U-shaped ridge with which this tubercle is crowned ; arms 

 of this ridge parallel or slightly divergent,' their extremities somewhat promi- 

 nent. Anterior margin of head slightly concave, with a slightly convex trans- 

 verse groove immediately behind it, meeting crest of supra-orbital ridge at 

 an angle of not more than 90°, and margin of canthus at an angle of about 120° ; 

 external angle of canthus about 120°; apical angle of supra-orbital ridge somewhat 

 more obtuse than this ; crest of supra-orbital ridge defined on inner side by distinct 

 groove ; a pair of more or less distinct ridges extending outwards and very slightly 

 forwards from base of anterior angles of central tubercle. Pronotiim smooth, 

 polished ; anterior margin almost straight, anterior angles rectangular, pointed but 

 not prominent ; sides parallel, posterior angles much rounded, posterior margin some- 

 what convex; margmal groove punctured, incomplete in the middle-line in front, 



' The type specimen of C. cormocerus, Zang, has the central tubercle of the form shown in the 

 last-mentioned figure, which is from a specimen from the Larut Hills, but the upper angle does not project 

 upwards, and occupies a much smaller part of the front of the tubercle than does the lower. 



* The width of this horn is very variable in proportion to its length even in our few specimens, all 

 of them ])robably from Johore. So Zang's suggestion (igSfl, p. 105) that Bornean specimens are 

 distinguished ))y a broad horn such as is figured by Kaup, and Malayan ones by a longer horn, can no 

 longer be maintained. 



