Mr. A. Murray on the Genus Cercyon. 75 



The above information clears up the synonymy of the genus 

 to a certain extent, and by examining Stephens's desci'iptions, 

 aided by the light derived from a comparison of the above spe- 

 cies which have been identified, with their descriptionSj and by 

 an examination of other cabinets in which I have found what 

 have been supposed by others to be the species corresponding to 

 Stephens's names, I shall venture to give a list of our British 

 Sphaeridiidse with a more extended synonymy — the rather, that 

 as I have explained my sources of information, no one can be 

 deceived into attaching more weight to my opinion than it is 

 justly entitled to. I adopt the arrangement and characters of 

 Mulsant, and I dare say it will be acceptable to our younger en- 

 tomologists, if I digest it into the shape of a short monograph, 

 noticing briefly those distinctive characters which can be readily 

 seized, but referring them to Mulsant and other authors for full 

 and extended descriptions. 



Mulsant divides the Palpicornes of France into two groups, the 

 HydrophilidjE and Geophilid^, which are distinguished from 

 each other by the former having the first article of the posterior 

 tarsi always shorter than the second, while the latter has it always 

 longer than the second. 



The group HYDROPHiLiDiE is composed of the genera Sperchetis, 

 Helophorus, Hydrochus, Octhebius, Hydrcena, Limnebius, Berosus, 

 Hydrophilus, Hydrous, Hydrobius, Laccobius, Helophilus, Phil- 

 hydrus, and Cyllidium. 



The group GEOPHiLiDiE, with which we have to do, is composed 

 of the genera Cyclonotum, Sphceridium, Cercyon, Pelosoma, Me- 

 gasternum, and Cryptopleurum. 



He separates the four first genera of this second group into 

 one division, " Spharidiares," distinguished by having the meso- 

 sternum much longer than broad, and compressed into a kind of 

 blade. The two last form another division, " Megasternares," 

 which has the mesosternum not longer than broad, and of an 

 irregular pentagonal form. 



The mesosternum also furnishes characters sufficient to di- 

 stinguish the four genera of Spharidiares from each other, viz. : — 



Cyclonotum. Has the mesosternum terminated in front by an arrow- 

 head shape ; scutellum almost an equilateral triangle. 



SphfEvidium. Mesosternum compressed into a blade of equal thick- 

 ness, not terminated in an arrow-head ; scutellum twice as long 

 as broad. 



Cercyon. Mesosternum sublinear, sharpened both before and be- 

 hind ; scutellum subequilateral, or not more than a half longer 

 than broad. 



Pelosoma. Mesosternum Hnear, but sharpened before and truncate 

 behind. 



6* 



