Ceylon Coleoptera, §c. 

 No. V. 



57 



The Trigonotomim: with an elliptic terminal joint of the 

 palpi are abundantly represented amongst the Ceylon Cara- 

 bidre, thus making amends for the want of other tribes of the 

 section to which they belong. I have now before me a great 

 many individuals of different species which I have endea- 

 voured to distribute into genera after the works of Lacor- 

 daire, Dejean and others of less importance. A single glance 

 almost convinced me that they must belong either to Abacetus, 

 Distrigus or Drimostoma — genera closely allied, and whose 

 principal, in fact only essential, distinction would appear to 

 reside in the shape of the mentum-tooth. If it is a well estab- 

 lished fact, as cannot be doubted from the above authors, that 

 this tooth is pointed in Drimostoma, large, rounded, equalling 

 the lateral lobes in Abacetus, and large and truncated in Di- 

 strigus, the species described below could not, as to their 

 genera, be distributed otherwise than I have done ; namely 

 5 Distrigus and 1 Drimostoma. The species which I have 

 drawn to the former genus have a large, more or less square 

 tooth, slightly rounded at the anterior angles. It is impos- 

 sible to call this tooth pointed in any of the five species ; they 

 cannot therefore belong to the genus Drimostoma, nor can 

 any of them be drawn to Abacetus, which genus is moreover 

 apparently exclusively African. As to the insect which I 

 have placed in the genus Drimostoma, its mentum-tooth is 

 not exactly pointed, but it is altogether narrower than in 

 Distrigus and might well be called " assez aigue," as Dejean 

 describes it. This insect differs, moreover, very materially 

 in general appearance as well as in its details from my Di- 

 strigi and I feel sure that it belongs to the genus in which 

 I have placed it, although it does not quite agree with La- 

 cordaire's description— the labruni being emarginated in front, 

 1857. I 



