370 INSECTA. 



FAMILY III. 



SERRICORNES(l). 



In the third family of pentamerous Coleoptera, as in the preced- 

 ing and following families of the same order, we find but four palpi. 

 The elytra cover the abdomen, which, with some other characters, 

 distinguish the Insects which compose it from the Brachelytra just 

 mentioned. The antennae, with some exceptions, are equal through- 

 out, or smaller at the extremity, dentated, either like a saw or a 

 comb, or even like a fan, and in this respect are most developed in 

 the males. The penultimate joint of the tarsi is frequently bilobate 

 or bifid. These characters are rarely found in the following family, 

 that of the Clavicornes, to which we arrive by such insensible gra- 

 dations, that to define its limits rigorously, becomes a 'very difficult 

 matter. 



Some, in which the body is always firm and solid, and most com- 

 monly oval or elliptical, with partly contractile legs, have the head 

 plunged vertically into the thorax up to the eyes; and the praester- 

 num, or median portion of the thorax, elongated, dilated or reaching 

 to beneath the mouth, usually distinguished on each by a groove in 

 which the antennae always short are lodged, and prolonged pos- 

 teriorly into a point, which is received into a depression of the ante- 

 rior extremity of the mesosternum. These anterior legs are at a 

 distance from the anterior extremity of the thorax. They form a 

 first section, or that of the STERNOXI. 



Others, whose head is enclosed posteriorly by the thorax, or at 

 least covered by it at base, but in which the praesternum is not di- 

 lated, and does not project anteriorly in the manner of a chin-cloth, 

 and is not usually terminated posteriorly in a point received into a 

 cavity in the mesosternum, and in which the body is most commonly 

 either entirely or partially soft and flexible, constitute a second sec- 

 tion, that of the MALACODERMI. 



A third and last, that of the XYLOTROGI, will comprise those 

 Serricornes, in which the posterior extremity of the praesternum is 

 not similarly prolonged, but whose head is completely exposed and 

 separated from the thorax by a strangulation or species of neck. 



(1) Saw-horned. 



