ORDER COLEOPTERA. 409 



approach the most to the following family. The antenna? of 

 the other Clavicornes of the same section, are composed of 

 eleven or ten articulations ; but sometimes they are but little 

 longer than the head, and form from the third articulation 

 an almost cylindrical or fusiform knob, arched, and a little 

 serrated. Sometimes they are almost filiform, of the length 

 of the head and the corslet. But here, as in the most pan 

 of the other sub-genera of the same division, the tarsi are 

 terminated by a large articulation, with two strong crotchets 

 at the end. Those of some have but four articulations. 



The body of these Coleoptera is generally ovoid, with the 

 head sunk as far as the eyes, in a trapezoidal corslet, edged 

 laterally, and terminated posteriorly by acute angles, the 

 presternum dilated anteriorly (the Potamophili excepted), 

 and the feet imperfectly contractile. They are found in 

 water, under stones, near shores, and often sunk in the mud. 

 By the construction and shortness of their antennas, some of 

 them (Dryops) have an affinity with the gyrini. 



I shall divide this section into two tribes. The first, that 

 of AcANTHOPODA, is remarkable for the flatted limbs, tole- 

 rably broad, and armed externally with spines. The tarsi 

 are short, with four articulations, the crotchets of which are 

 of the ordinary size, and the body of the animal is depressed. 

 The presternum is dilated. The antennae are a little longer 

 than the head, arched, with eleven articulations, the last 

 six of which form a knob, almost cylindrical, and a little 

 denticulated, like a saw. The second is short, and without 

 dilatation. 



This tribe is composed of a single genus, that of 



Heterocerus, Bosc. Fab. 

 These insects remain in the sand or in the mud, near the 

 borders of rivulets and marshes, and come out of their holes 

 when they are disturbed by any one walking near them, or 



