28 COLEOPTEKA. 



in the Brachdytra, yet they might almost as well be included 

 in the Necroplmga, being closely allied to the Scydmcenidce. It 

 has often been remarked that our systems are only approxima- 

 tions to a natural arrangement at best, for we not only find it 

 difficult to lay down characters which shall hold good Avithcut 

 being liable to many exceptions, but even if we find such 

 characters, they are always more or less arbitrary, and frequently 

 result in our systems widely separating groups that are in reality 

 more or less closely allied. 



SECTION IV.— Necrophaga. 



Tarsi generally five-jointed; antennae of moderate length, gene- 

 rally clavate ; elytra generally covering the abdomen. 



The Necropliaga or Clavicornia are an extensive and varied 

 group, including, besides the families which strictly belong to it, 

 several of somewhat doubtful position. A great number feed on 

 decaying animal matter, others are found in dung or among 

 vegetable refuse, and several species inhabit ants' nests. 



Some of the smaller families of this group will be left un- 

 noticed here. 



Family T. — Paussidce. 



Body depressed, oblong, antennae either two-jointed, the second 

 joint being triangular or ovoid, or with from six to ten much 

 enlarged joints ; palpi large, conical ; elytra truncated at the tip ; 

 tarsi short, four-jointed. 



This is a very remarkable family of beetles, and its position 

 has been much debated by entomologists, several of whom have 

 referred it to the Carabidce, while others have considered it to be 

 nearer allied to the Xylophaga. The species are of small size, and 

 almost exclusively exotic, only one or two having been observed 

 in South Europe. They inhabit ants' nests, where they pro- 

 bably fulfil the functions of artillerists, for when disturbed they 

 discharge a volatile detonating fluid like Brachinus, and although 

 less in quantity, it is so highly corrosive that its stains take many 

 days to disappear from the hands. 



The extraordinary antennae render the Paussidce unmistakeable; 

 and in some species, such as Homopterus Brasiliensis, Westw., a 

 reddish-fulvous insect a quarter of an inch long, the legs are 

 remarkably dilated as well. Two other species of the family are 



