88 Mr. A. Murray on the Genus Cercyon. 



sternum broader than long and irregularly pentagonal. It con- 

 tains only two species so far as yet known, each of which has 

 been constituted by Mulsant into a separate genus. 

 The characters are as follows : — 



Megasternum. Sides of thorax not turned in below ; presternum 



lozenge-shaped, longitudinally keeled. 

 Cryptopleurum. Sides of thorax folded in below in the form of a 



triangle ; prosternum pentagonal, with its broadest side in front. 



Megasternum, Muls. 



Cercyon, Steph. 



M. Boletophagum, Erich., Muls., Steph. 

 acutum, Steph. 

 immune, Kirby, Steph. 

 stercorarium. Marsh., Steph. 

 immaculatum, Kirby, Steph. 

 l(Bve, Marsh., Steph. 

 contaminatum, Kirby, Steph. 

 ferrugineum. Marsh., Steph. 

 concinnum, Marsh., Steph. ? 

 fuscescens, Steph. ? 

 testaceum, Steph. ? 

 immundum, Steph. ? 

 castaneum, Heer? 



Short, oviform, decidedly convex, shining brownish black 

 above. Head and prothorax punctate. Elytra diminishing to 

 the apex, with ten slight rows of punctures; intervals more 

 finely punctate than the thorax. 



Length | to 1 line ; breadth ^ to | of a line. 



The shape of the mesosternal plate and prosternum at once 

 easily distinguish this from all the other species of Cercyon ; but 

 its body above is also recognizable by a glassy semitransparent 

 lustre which no other species has. It is exceedingly variable in 

 size and colour, and in depth of striae and punctuation. Some- 

 times it is a full line in length, occasionally not much more 

 than half a line. It is generally dark chestnut-coloured, but 

 sometimes quite black ; sometimes the strise are well-defined, 

 at others scarcely perceptible, but the form of its mesosternal 

 plate, its glassy lustre, and a peculiarity in the puncturing of the 

 strise will always distinguish it. The punctures in the striae are 

 not as if they had been impressed vertically, as is usually the 

 case, but as if a needle had been held slanting forwards and a 

 succession of nearly horizontal pokes had made the punctures. 



Notwithstanding the great variety in the points to which I 

 have alluded, there is no insect in the group more readily recog- 



