56 THE ENTOMOLOGIST. 



Cryptopleurwn the prosternum ends in two points behind, and 

 the mesosternum is very broad. Of the latter two genera, 

 Megasternum has the sides of the thorax not reflexed, and the 

 anterior tibiae strongly excised outside at the apex ; while Crypto- 

 pleurum has the sides of the thorax reflexed, and the anterior 

 tibise entire. 



The several species, however, may be easily distinguished 

 without having recourse to the under side, and it will perhaps be 

 best to say a few words about each in turn, dividing the Cercyons 

 for this purpose into five groups. 



The first group may be said to consist of C. obsoletus, 

 C. hcemorrhoidalis, C. hcemorrhous, C. aquaticus, C. flavipes, and 

 C. lateralis. 



C. obsoletus, Gyll., is the largest species of the whole group, 

 and may easily be distinguished by its size and nearly round 

 form ; in case, however, of any difficulty arising, it may be at 

 once known by the fact that it has no impression at the base of 

 the thorax : it is decidedly a rare species, and apparently prefers 

 haystack refuse to dung. It has been found at Han well, Ealing, 

 Notting Hill, Lee, Lerwick, and, I believe, near Burton-on-Trent. 



C. hcemorrhoidalis, F. — The smaller size and more pointed 

 elytra of this species distinguish it from C. obsoletus, which it 

 much resembles in striation and punctuation ; it possesses a 

 strong depression at the base of the thorax. From C. hcemorrhous 

 it may be separated by having the colour at the apex of the 

 abdomen much less distinctly defined, and by the less strong 

 punctuation of the interstices of the elytra. This is a common 

 species. It is very abundant in hotbeds and dung. 



C. hcemorrhous, G-yll., may be at once separated from the pre- 

 ceding by the small but distinct longitudinal impression at the base 

 of the thorax above the middle of the scutellum, by its narrower 

 shape, and by having the colour at the apex of the abdomen 

 much more marked : its strong striation will also serve to dis- 

 tinguish it. Common in mud and by ditches. 



C. aquaticus, Muls., may be at once separated from all other 

 species by having not only the apex but also the margins of the 

 elytra and thorax of a light red colour, the colour being most distinct 

 and well defined, with no transitional space between the black and 

 the red : it is a rare and local species, and appears to be entirely 

 subaquatic. Dr. Power has taken it at Notting Hill and in 

 Sheppy. 



