274 [December, s 



ON SOME SPECI?:S HITHERTO ASSIGNED TO THE GENUS CERCTOX 

 (COLEOPTERA, HTDROPHILIDAE), 



BY D. SlIABP, M.A., F.K.S. 



The little insects to which I am calling attention differ from the 

 other species of Cercyon bj a diameter that has hitherto escaped atten- 

 tion. The Cercyons possess a peculiarity in having on the metasternum 

 an area in the middle differently sculptured from the rest of the stern ite. 

 In the C. minutus group, this area becomes much elevated in front, 

 and stretches forwards to the strongly-elevated mesosternal lamina, with 

 which in most of the species it comes in contact, thus leaving above 

 the point of conjunction a peculiar lumen, or little vacant space. In 

 order to appreciate this character it is necessary to view the under surface 

 of the insect in profile. In addition to this peculiarity of the structure, 

 there is also a distinction from ordinary Cercyon inasmuch as the diffuse 

 punctuation of the elytra is reduced to vestiges of a few obsolete punc- 

 tures irregularly placed. Also the species are never found in dung. 

 These points would justify us in separating the group as a distinct genus. 

 Key placed them in his subgenus Cerycon^ of which he says : " ce sous- 

 genre remarquable se distingue, en outre, par son aire mesosternale plus 

 brusquement et plus fortement relevee " (*' Palpicornes," p. 844). But 

 he missed the important points of a similar elevation of the metasternum, 

 and the correlative relations of the two parts. He also placed C. hifene- 

 stratus in the subgenus, but as I have never seen that species I cannot 

 speak of it. On the whole it appears to me that it will be best to treat 

 Cerycon as a distinct genus, amending Key's definition and leaving it 

 doubtful whether C. hifenestratus belongs to it. Rey gives the meso- 

 sternal lamina as being "ovale ou naviculaire," but he missed the fact 

 that it is narrow in C. lugubris. C. minutus may be taken as the tj'pe, 

 it being the best known of the species, though structurally it is the 

 least advanced of the genus, the little C. sternalis being the most 

 differentiated. 



I desire to thank Mr. Champion and Commander Walker for lending 

 me their collections of these rare little insects. 



1. — Cerycon minutus, Fabr. 



This species is easily enough distinguished from all the others by 

 the obsolescence of the striae towards the extremit}' of the elyti-a ; the 

 sutural stria is continued to the apex, but the others quite fade away ; 

 the apex is very indefinitely and obscurely paler than the last ; the striae 

 at the base are well-marked and their punctures distinct. The palpi are 

 piceous, or flavo-piceous. The mesosternal lamina is rather broad, very 



