COLEOPTERA. — GYRINIDJE. Ill 



mentioned above, observed by Mr. Patterson, will be sufficient to show 

 the necessity of separating this insect from the other Gyrinidae. The 

 exotic genera do not require any especial notice. 



The second subtribe of the Pentamerous beetles, forming the tribe 

 Chilopodomorpha MacL., has been termed by Mr. Stephens, RYPO- 

 PHAGA (or Cleansers), from the important offices assigned to its 

 various members, of removing animal and vegetable substances in a 

 state of decomposition ; and is distinguished by having only four 

 palpi, viz. the labial and external maxillary, the internal maxillary palpi 

 being represented by the dilated external lobe of the maxillae, which 

 here loses its palpiform appearance, although occasionally evidently 

 articulated, and acquires the typical structure of the Coleopterous 

 maxilla;. The antennae are also of a more complex structure, being 

 either gradually or abruptly clavate, and the basal joints of the male 

 tarsi are generally more or less dilated. 



This subtribe appears to comprise the three following stirpes : — 



PHILHYDRIDA, typified by the genus Hydrophilus. 



Elytra covering the abdomen ; legs subnatatorial ; antennae 

 capitate. 

 NECROPHAGA, typified by the genus Silpha. 



Elytra generally covering the abdomen ; legs cursorial ; antennae 

 often capitate. 

 BRACHELYTRA, typified by the genus Staphylinus. 



Elytra very short, not covering the abdomen ; legs cursorial ; an- 

 tennae gradually clavate. 



But it is evident that several of the families placed by Mr. MacLeay 

 in the Chilognathiform (luliform) tribes, ought to find a station 

 amongst the Necrophagous Rypophaga. 



The stirps PHILHYDRIDA MacLeay (or lovers of water) is com- 

 posed of insects having either aquatic or subaquatic habits, residing in 

 the water, or in the damp margins and shores of streams and ponds. 

 Theyare distinguished from the other water-beetles by the shortness of 

 their clavate antennae, which often (although only, perhaps, in appear- 

 ance) possess fewer than the general number of joints, and by the ordi- 

 nary great length of their maxillary palpi, whence the typical groups 

 have been named Palpicornes by the French entomologists; the man- 



