HEXARTHRTUS. 73 



TIic trout lil>i;r mv slcmlcr, tlio lateral ttctli tew and iiiiimte 

 and tlu* terminal fork I(tnL^ Tiic middle tiltia has a striini! 

 lateral spine and the hind til»i;i has none. 



(J. Length (with mandil)les), 7(1 mm. : (witlioiit mandibles) 

 40 mm. : brefidth, 20 mm. 



" India." 



Type in the British Museum : eo-type in M. Rene Oberthiir's 

 collection. 



I liave seen only the sini^le male s])eeimen in the British 

 Museum, derived from the Bowring collection and of unknown 

 origin. It may ])erhaj»s he an inhabitant of Burma. 



24. Hexarthrius aduncus. (Plate VI, tig. 2.) 



Hexartkrius aduncus Jord., Xov. Zool. i, 1S94, p. 4S4, pi. 13, fip. 1 



(J. Reddish-chocolate, with the head, mandibles and tarsi 

 nearly black, the el>i:ra deej) reel and the abdomen, femora 

 and tibi» bright red. Bather narrow in shape, with the head 

 and pronotum dull and the mandil)les and elytra smooth and 

 shining. The head is densely granulai-, the front angles are 

 rather sharp and the sides swollen behind the eyes. The 

 tifth joint of the antenna sharply produced. The mandil)les 

 are slender, not strongly curved or detlected. The cly])eal 

 process is bluntly pomted and not toothed at the base. The 

 sides of the pronotum are densely granular but the granules 

 are finer and less dense in the middle. The front angles are 

 rather sharp, the lateral maigins irregularly dentate, almost 

 .straight to the middle, then rounded, with an acute lateral 

 tooth beyond the middle, and almost straight to the hind angle, 

 whiQh is W'cll marked. The ■^cntellnw is tinely granular. 

 The elytra are very smooth but the anterior part of the lateral 

 margin is a little dull. The front tibia is slender, minutely 

 serrate externally, with a few short teeth, the terminal fork 

 is strongly bent downwards and there is a sharj) s])ine beneath 

 at the base of the tarsus. The middle tibia bears a strong 

 lateral spine and the hind tibia has none. The prosternnm 

 is a little compressed behind but not ])ointe(l. 



Variation of the male. In small sjjccimens the mandibles 

 are tlattened, horizontal, gently curved externally and bear 

 a small sharp internal tooth at the base and another a little 

 before the tip. In medium-sized males a small internal tooth 

 appears a little beyond the basal one and a still smaller one 

 innnediately Ijcfore the tip. In large specimens the mandibles 

 are not tlattened, they are curved downwards but ap])ear 

 . rather straight as seen from above, exce])t at the base and 

 extremity. The basal tooth is bhmt and directed obliquely 

 backwards and, in addition to the teeth, a few ill-defined and 

 variable tubercles ma}' be found at the inner edge. 



