COLEOPTERA. 369 



PASSALUS, Fabricius, 



Restricted by M. Mac Leay to those species in which the club of the antennae 

 consists of but three joints, where the labrum forms a transversal square, and 

 the maxillae have three strong terminal teeth, and two on the inner side in 

 place of the anterior lobe. 



These insects are foreign to Europe, and, as it would appear, to Africa, 

 being chiefly found in the eastern parts of Asia, and particularly in America. 

 Madame Merian says, that the larva of the species figured by her lives on 

 the roots of the sweet potato. The perfect insect is not uncommon in the 

 sugar-houses. 



In the second general section of the Coleoptera, or the HETEBOMERA, we 

 find five joints in the Jour first tarsi, and one less in the two last. They all 

 feed on vegetable matters. 



In some, where the elytra are generally solid and hard, and the hooks of the 

 tarsi are almost always simple, the head is ovoid or oval, susceptible of being 

 received posteriorly into the thorax, or sometimes narrowed behind, but not 

 abruptly, and without a neck at its base. Many of these Heteromera avoid the 

 light This division will comprise the three following families. 



FAMILY I. 



MELASOMA. 



THIS family consists of unmixed black or cinereous coloured insects (from 

 which is derived the name of the division), mostly apterous, and frequently 

 with soldered elytra. Their antenna?, entirely or partly granose, almost of 

 equal distance throughout or slightly inflated at the extremity, and the third 

 joint wholly elongated, are inserted under the projecting edges of the head. 

 The mandibles are bifid or emarginated at the extremity; the inner side of 

 their maxillae is furnished with a corneous tooth or hook, all the joints of the 

 tarsi are entire, and the eyes oblong and but very slightly prominent, a 

 circumstance which, according to M. Marcel de Serres, indicates their noctur- 

 nal habits. Almost all these insects live on the ground, either in sand, or 

 under stones, and frequently in cellars, stables, and other dark places about 

 our habitations. 



Our first division of this family, which in the Linnsean system forms the 

 genus TENEBBIO, is founded on the presence or absence of wings. 



Of those which are deprived of these organs, and in which the elytra are 

 generally soldered, some have the palpi almost filiform, or terminated by a 

 moderately dilated joint, and do not form a distinctly securiform or triangular 

 club. They will compose a first tribe, that of the PIMELIARI.S:, so named 

 from the genus 



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