COLEOPTERA. 



441 



mandibles strong and much dentated, but without any very 

 remarkable sexual difference ; the maxillae entirely corneous 

 with at least two strong teeth ; the ligula equally corneous or 

 very hard, situated in a superior emargination of the mentum, 

 and terminated by three points ; the abdomen pediculated, 

 presenting the scutellum above, and separated from the thorax 

 by a strangulation or considerable interval. They form the 

 genus 



Passalus, Fab. 



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 interior lobe. 



The species, in which the club is composed of five joints, the la- 

 brum is very short, and the maxillae have but two teeth, one terminal 

 and the other on the inner side, form his genus Paxillus. 



Finally, in his family of the Passalides, he unites to the preceding 

 the genus Chiron, which we have placed in the tribe of the Copro- 

 phagi(l). 



These Insects are foreign to Europe, and as it would appear, to 

 Africa, being chiefly found in the eastern parts of Asia, and parti- 

 cularly 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(2). 



In the second general section of the Coleoptera, or the 

 Heteromera, we find five joints in the four first tarsi, and 

 one less in the two last. 



These Insects all feed on vegetable substances. M. Leon 

 Dufour Annal. des Sc. Nat., VI, p. 181 has observed that 

 the texture of the male organs of generation approximates 

 them to those of the Scarabaeides and Clavicornes ; their 

 testes consist of spermatic capsules or sacculi. 



(1) Hor. Entom. I, p. 105, et seq. 



(2) See Fabricius, Syst. Eleuth , II, p. 155; Web., Obser. Entom.; Palis, de 

 Beauv., Insect. d'Afr. et d'Ame>.; Lat., Gener. Crust, et Insect., II, p. 136; and 

 Schcenh., Synon., I, iii, p. 331, and Append., p. 143, 144. 



Vol. III. 3 F 



