HEXARTHRIUS. 09 



are tiiu'ly and clost'ly |»uii('tiin'(l. 'I'lir i'loiil Hhl<i, hears very 

 sliarf* lateral teeth, th(^ middle til)ia a str()ii<r lalenil spine and 

 the hind tihia a ieel)le one. 



Voridtion of the inalf. In small s])eeimens Iho head is oidy 

 very sliglitly convex on each .sick' of the middle, the elypeal 

 process is transversely pentagonal, the mandibles are feef)ly 

 curved externally and shghtly arched, with a small sharp 

 inner tooth beyond the mifldle and another before the tip, the 

 inner edge l)etween the teeth finely crenulate. In larger 

 sj)ecinien8 the head has a broad median depression and a 

 distinct swelling on each side of it. The three anterior angles 

 of the clyjieal process are a little more jirominent and the 

 middle one is sharply retlexed. I'lie mandibles are stouter, 

 more strongly curved and arched but not longer relatively. 

 There is a slight sharp tooth directed upwards at tlie base 

 and a similar one beneath directed downwards. The post- 

 median tooth is strong and sharj), there is a row of rather 

 strong tubercles before and after tlie ante-apical tooth and the 

 basal inner edge is finely crenulate. In large specimens the 

 head is very broad and strongly swollen on each side and the 

 mandibles are very stoiit. 



3*. Length (with mandibles), 4S-S0 mm. ; (without mandibles) 

 37-()l mm. : breadth, ir)-2r)mm. 



2. Length. 40-44 mm. ; breadth, I()-20 nun. 



Assam : Shillong, Khasi Hills ; Cachar ; Sylhet. 



Type in M. Rene Oberthiir's collection. 



This is one of the most distinctive of all Indian s])ecies but 

 it has a very close similarity to Hexarthrins deyrollei Parry, 

 which has a wide distribution in Indo-China, the Malay 

 Peninsula, Sumatra and Java. In that form the yellow 

 elytral patch in the male is rather smaller, the two elevations 

 U))on tlie head are more strongly developed and conic-al and 

 the upi)er basal tooth of tlie mandil)le is stronger and continued 

 by a toothed ridge on the dorsal surfoce. The female is more 

 elongate than that of H. parryi. 



21 . Hexarthrius forsteri. (Plate V, tig. ."> ; Plate VI, fig. 1.) 



LucdHiis forsteri Hope.* Trans. Linn. Sor. Lond. xviii, 1841. p. .")S7. 



pi. 40, %. I. 

 He.rarthrhi.s forsteri Boil., Tnms. Knt. Soc. Lond. 191.3, j). 222. 



Rather narrowly elongate, the male reddish-brown in colour, 

 with the mandibles and eh'tra very glossy, the female black 

 and rather dull. The lateral margins of the prothorax finely 

 and irregularly serrate or crenulate and the hind angles well 

 marked. The ])rosternum jirominent and com])re.ssed but not 

 produced behind. The fifth joint of the antenna strongly 

 produced. 



^. Entirely black, not shining, not very long. The head 



