paussid^;. 



445 



and prominent, and at the sides, just before apex, there is in the 

 majority of cases, a small expansion or fold. 



Wings well developed in all cases, with somewhat irregular and 

 broken venation, but plainly of: the adephagid type (vide p. 41). 



Legs almost always robust, with the femora and tibiae often, 

 much dilated and compressed ; coxae of the anterior and inter- 

 mediate pairs round, of the posterior transverse ; trochanters 

 large and well developed ; tarsi always five-jointed, with the last, 

 joint elongate, sometimes as long as the four preceding together ; 

 all the joints are simple and entire and never bilobed ; in some 

 genera the first four are dilated and strongly pubescent beneath 

 in the male; the claws are always two in number, and are strong 

 and simple. 



Fig. 200. — Wing of Paussus latus, Gerst. ; Abyssinia. (After Raffray.) 



Abdomen with five ventral segments visible along the middle 

 and six at the sides, as is generally the case in the families of the 

 Adephaga. Stigmata, fourteen (Kaffray) or sixteen (Desneux) 

 abdominal, and four thoracic. The shape of the genital arma- 

 tures is very variable, and affords good characters, but this need 

 not be discussed here ; a detailed account will be found in 

 Kaffray's work (Nouv. Arch. Mus. Paris, (2) viii, 1885, p. 325) 

 and several of the armatures have been figured by him. 



Habits. 



We have already discussed, in the general Introduction, the 

 question of the position of the Paussid^e, and this need not again 

 be referred to. The habits of the family are very interesting. Its 

 members are mainly, if not entirely, myrmecophilous, and they 

 appear to be almost exclusively found in or near ants' nests, or 

 flying to light. They have the power of crepitating, and discharge 

 a volatile fluid from the anus, with an explosion. This fluid is 

 caustic and discolours the flesh ; Loman, and after him Escherich, 

 have recognized in it the presence of free iodine. Some of the 

 larger species, such as Cerapterus stall (which is almost as large as 

 a Geotrujpes), make quite an alarming noise when disturbed. 

 Besides this defensive secretion, it is evident that a large number 

 of the species have the power of secreting a substance that is 

 pleasing or nourishing to the ants with which they live, and the 



