ORDER COLEOPTERA. 539 



salivary. As in the pentamera, the hepatic vessels, with few 

 exceptions, are six, and have two insertions distant from 

 each other : at one end, says M. Dufour, they are inserted by 

 six isolated nippers, round the convexity which terminates 

 the chylific ventricle. The other ends open at the commence- 

 ment of the coecum, by trunks, whose number varies accord- 

 ing to the family and genus. 



Some, whose elytra are generally firm and hard, whose 

 hooks of the tarsi are almost always simple, have the head 

 ovoid or oval, capable of being withdrawn backward under 

 the corslet, or narrowed sometimes behind, though not sud- 

 denly, and without a neck at its base. Many of these Hete- 

 romera are lucifugous. This division will include the three 

 following families. 



The first, that of 



Melasoma, 



Is composed of insects of a black or ash-colour, without 

 mixture, whence the section is named ; apterous, for the 

 most part, and with the elytra oftentimes soldered together ; 

 the antennae altogether, or in part granulated, nearly of the 

 same thickness throughout, or a little enlarged at the ex- 

 tremity, inserted under the advanced edges of the head, with 

 the third articulation in general elongated ; the mandibles 

 bifid or emarginated at the extremity, and having a careous 

 tooth or hook on the inner side of the jaws. All the articu- 

 lations of the tarsi are entire, and the eyes are oblong, and 

 but little elevated, a character which, according to M. Marcel 

 de Serres, indicates their nocturnal habits. Nearly all these 

 animals live on the ground, either in sand or under stones, 

 and often also in the low and dark parts of houses, as cel- 

 lars, stables, &c. 



According to M. Leon Dufour (Ann. des Sciences Nat. v. 

 276), the biliary vessels are inserted on the inner side of the 



