298 DYNASTIN.E. 



Genus ALISSONOTUM. 

 Alissonotum, Arroio, Trans. Ent. Soc. Lond. 1908, p. 322. 



Type, Geoimpes piceus, Y. 



liamje. Southern Asia. 



Ovate or cylindrical in form, convex, smooth and shining. 

 Clypeus attenuated and bidentate in front, the suture represented 

 by a pair of transversely placed tubercles. Organs of the mouth 

 as in Heteronijclius, the mandibles bilobed externally. Pronotum 

 distinctly punctured and sometimes slightly impressed behind the 

 middle of the front margin, regularly rounded and not closely 

 fringed at the sides. Front tibia tridentate, with minute denticles 

 before and after the uppermost tooth. Hind tibia flattened and 

 spinose and tarsi slender. Propygidium bearing two narrow 

 longitudinal stridulatory files. 



The sexes are alike and the front tarsi not thickened, but the 

 inner claw of the male may become very feebly enlarged. 



The strongly striated elytra and functional stridulatory files, as 

 well as the rather differently formed hind legs, distinguish this genus 

 from Pentodon. In the latter there are sometimes traces of a 

 double series of ridges upon the propygidium, but the files are always 

 very coarse and imperfect and the ridges do not nearly reacli the 

 hinder margin of the segment. The recognised species of Pentodon 

 are very homogeneous in size and form and are essentially Palae- 

 arctic in distribution, whereas the present group consists of smaller 

 species of rather varied form and is apparently confined to 

 Tropical Asia. 



Key to the Species. 



1 (8) Pronotum witliout un anterior mar^nal 



pit. 



2 (5) ProiiotiHu very finely and unequally 



punctured. 



3 (4) Body short piceum, F., p. 299. 



4 (3) Body long elongatum, sp. n., 



5 (2) Pronotum coarsely punctured. [p. 299. 

 G (7) Punctures of the pronotum not crowded 



at the sides rangunense, sp. u., 



7 (6) Punctures of the pronotum crowded at [p. 300. 



the sides simile, sp. n., p. 300. 



8 (1) Pronotum having a small anterior mar- 



ginal pit. 



9 (10) Pronotum not very coarsely or closely [p. 301. 



punctured impressicolle, Arrow, 



10 (9) Pronotum very coarsely and closely punc- 



tured. 



11 (12) Hind angles of the pronotum completely [p. 301. 



rounded binodulwn, Fairm., 



12 (11) Hind angles of the pronotum not com- [p. 302. 



pletely rounded crassum, Arrow, 



