COLEOPTERA. 39 



tube intestinal des Irisectes, Ann. du Mus. d'Hist. Nat. — has care- 

 fully studied the texture of the tunics of the alimentary canal *. The 

 adipose tissue is more abundant in these Heteromera than in the fol- 

 lowing ones, which enable them, even when transfixed and confined 

 with a pin, to live six months without food, a fact I have witnessed in 

 an Akis. 



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

 forms the genus Tenebrio, is founded on the presence or absence of 

 wings. 



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

 tra are generally soldered, some have the palpi almost filiform, or ter- 

 minated 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^, so named from the genus 



PiMELIA, Fab. 

 Which is the most numerous of the whole. 



Sometimes the mentum is more or less cordiform, the superior mar- 

 gin either emarginated in the middle, and divided as it were into two 

 short and rounded lobes, or broadly emarginated or widened. 



Here, the two last joints of the antennse, or the tenth or eleventh, 

 always distinct, sometimes unite to form an ovoid or pyriform body, 

 or are evidently separated from each other. The superior margin of 

 the mentum is rounded and emarginated in the middle, or as if 

 divided into two festoons. 



These have the anterior margin of the head almost straight or pro- 

 jecting but slightly in the middle, without a profound emargination 

 for the reception of the mentum, and its lateral margin simply and 

 slightly dilated above the insertion of the antennae ; the head does 

 not seem to be sensibly narrowed behind, nor widened and truncated 

 before. The thorax is not cordiform, deeply emarginated before and 

 truncated posteriorly. 



From these last, we may separate those in which the anterior mar- 

 gin of the head is straight, or nearly so, without any angular or den- 

 tiform dilatation in the middle, in which the almost square and mode- 

 rate sized labrum is entirely exposed, the thorax is transversal, and 

 the abdomen extremely voluminous and inflated. 



Those, in which the body is more or less ovoid or oval, the thorax 

 narrower than the abdomen even at base, generally convex, without 

 acute prolongations at the posterior angles, and without a posterior 

 projection to the praesternum, compose the subgenus properly called 



* What M. Dufour styles the chylific ventricle, M. de Serres calls the stomach, 

 aad, relative to other Insects, the duodeaum. What he calls the small intestine is 

 considered by the first as the ca;ciim. According to M. Dufour, M. de Serres 

 has not mentioned the crop of the Melasoma, although in Akis and Pimelia it is very 

 apparent. 



