HETEROCHTHES. 211 



(^. Length (with mandibles), 14-30 mm. ; (without man- 

 dibles) 13-23 mm : breadth, ^^Alxwrn. 

 $. Length, 15-18 mm. ; breadth, 7-8 mm. 



TeNASSERIM. M.\LAY PENrSSULA. 



Type in the Hope Dei)artment, Oxford University Museum. 



This rather peculiar and isolated species, which has been 

 found in considerable num})ers in the Malay Peuhisula. is 

 especially remarkable for the com})lete contrast between the 

 two male i)hases, the very \musual form of tlie mandibles in 

 the constant phase and their feeble development in the incon- 

 stant phase. The largest examples I have seen belong to the 

 latter, which is more abundant than the former. 



Genus HETEROCHTHES. 



Heterochthes Westw., Trans. Ent. Soc. Lond. (3) ii, 1864, p. 17 ; 

 Leuthner, Trans. Zool. Soc. Lond. 188.5, p. 479. 



Type, Heterochthes brachypterus Westw. 



Range. Cambodia, Andaman Is. 



Body short and broad, with the legs not long, the tarsi very 

 short and thin. Eyes completely divided by the canthus and 

 the upper and lower halves very small ; the head a little 

 swollen behind tlie eyes in both sexes. Pronotum short, with 

 the sides vey bluntly angulate and hijtid angles absent. El\-tra 

 very short, with rounded sides and blunt shoulders. ^liddle 

 and hind tibiae short, without lateral spines. Prosternum 

 grooved between the coxae, slightly compressed behind bnt 

 not very prominent. Clypeal process extremely short. 



(J. Head very broad, not emarginate in front, feebly prom- 

 inent in front of and behind the eyes. Elytra extremely short. 

 Front tibiae slightly elongate. Antennae rather short . 



O. Head bluntly prominent in front of the eye. IMandibles 

 narrowed beyond the base, l)road and opposable at the end , 

 leaving an intermediate gap. 



Heterochthes differs markedly from Calcodes by its peculiar 

 shape, very small eyes, the complete absence of hind angles 

 to the pronotum, the short thin tarsi, abbreviated elytra of the 

 male and peculiarly shaped mandibles of the female. 



119. Heterochthes andamanensis. (Plate XXI, figs. 10-12.) 



Heterochthes andamanensis Westw.,* Tran.s. Ent. Soc. Lond. 1874, 

 p. 359, pi. 3, fig. 2 : Leuthner, Trans. Zool. Soc. Lond. 1885, 

 p. 480,pl. 84, figs. 9-12. 



Black, with the elj-tra very dark brown, the tibiae and tarsi 

 bearing inconspicuous pale hairs. 



5. Tlie head is rather finely punctured and opaque, except 

 beliind and at tlie sides, wliere it is very coarsely punctured 

 and shming. It is strongly and almost angularly dilated on 

 each side in front. The mandibles are fairly long, very coarsely 



p2 



