COLEOPTER A. 4 05 



All the Byrrhii remain on the ground in sandy localities *. 



It is imj'o.vNible to <i .u Clavicornes of our second section, 



although :i \vry natural one, but by the reunion of several characters. 

 %gne of these Insects are removed from all Others of the family by 

 their antennae, which consist of nine or six joints ; they are those, 

 which, in this respect, seem to approximate most closely to the Palpi- 

 cornes. The antennae of the other Clavicornes of the same section 

 are composed of eleven or ten joints ; but sometimes they are not 

 much longer than the head, and from the third joint form an almost 

 cylindrical or fusiform club, arcuated and somewhat serrated ; some- 

 tinu's they are nearly filiform and as long as the head and thorax 

 united ; but here, as in most of the other subgenera of the same divi- 

 sion, the tarsi are terminated by a large joint furnished with two 

 strong terminal hooks. Those of some Heterocerus, Georissus 

 consist of but four join 



Tin- body of these Insects is generally ovoid, and their head 

 plunged to the eyes in a trapezoidal thorax, with a recurved lateral 

 margin, and terminating posteriorly in acute angles ; the praester- 

 num is dilated anteriority f, and the legs are imperfectly contractile. 

 They are found in the water, under stones in the vicinity of shores, 

 and frequently in the mud : some of them Dry ops are allied to the 

 Qyrini by the structure and shortness of their antennae. 



I will divide this section into two tribes J. The Insects which com- 

 pose the first or the ACANTHOPODA are remarkable for their flattened 

 and tolerably wide tibiae, armed anteriorly with spines; for their 

 short quadriarticulated tarsi, the hooks of which are of the usual size; 

 and for their depressed body. The praesternum is dilated. The an- 

 tennae are a little longer than the head, arcuated, and formed of 



* For the other species, see Fabricius, Olivier, Schoenherr, Gyllenhal, &c. 



The grnns MURMIDIUS, Leach, according to that gentleman, belongs to this tribe. 

 The antennae arc composed of but ten joints, the last of which forms an ovoido-glo- 

 bular club. Sec Lin. Trans., XIII, p. 41. 



f The Potamophili excepted. 



t We might also divide the section ia the following manner : 



I. Antennae composed of eleven joints. 



A. Antennae clavate and very short. 



a. Tibiae spinous ; tarsi quadri- articulated. 



HKTKROCBEUS. 



b. Tibiae simple ; five joints in the tarsi. 



POTAMOPHILUS. DRYOPS. 



B. Antennae filiform or slightly enlarged near the end, as long as the head 

 and thorax. 



Kuans. 



II. Antennae nine or six joints. 



MACROXYCHUS. Gcoussus. 



VOL. in. H H 



