HETEROMEROUS GROUND-BEETLES. 121 



vate aud mouiliform aiiteiinse, and their uniformly dark or blacjk colora- 

 tion. The above name of Latreille, meaning hlacJc-hodied, is expressive 

 of this character. As a general rule they are rather large beetles, many 

 of them being above the medium size, and few much below it. They 

 are found almost exclusively upon the ground, and mostly in sandy situ- 

 ations. Scarcely any observations appear to have been made respect- 

 ing the food-habits of these beetles, with the exception of a few common 

 species which inhabit houses and granaries, the larvaj of which are some- 

 times seriously injurious to flour and meal of different kinds. The larvte 

 of a few species have been found in rotten wood. All the known larvae 

 are very similar in form and structure, and are well represented by the 

 common meal-worm which is the larva of the Tenebrio moUtor, Linn. 

 This is a long, slender, cylindrical grub, of a wax-yellow color, and a 

 hard consistency. In its motions it seems to drag its body along by 

 means of the six short legs attached to the three anterior segments, its 

 comparative inflexibility incapacitating it for the vermicular motion by 

 which the softer larvjc effect their progression. 



A comparatively small proportion of the insects of this tribe inhabit 

 the northern and eastern sections of this country. Their geographical 

 center is in the tropics, and they constitute a leading feature in the in- 

 sect fauna of California, and other portions of the Pacific slope. 



The several groups of which this tribe is composed are found to pass 

 so insensibly into each other, when the species from all parts of the 

 world are compared together, that Lacordaire, in his great work on the 

 genera of Coleoptera, unites them all in the one large family of Tene- 

 brionidai, in which he also includes the fungus-beetles {DiaperUJcv). In 

 this course he has been followed by our owq distinguished coleopterist. 

 Dr. John L. LeConte, and more recently by Dr. George H. Horn, of 

 Philadelphia, who has published an elaborate monograph of the K A-. 

 species of this family. 



In speaking of the unusual difficulties which are met with in classify- 

 ing this tribe of insects, M. Lacondaire makes some remarks which are 

 so pertinent to the case, and at the same time so comprehensive, that 

 we here introduce them : 



" Our classifications of insects are based, not upon isolated characters, 

 but upon combinations of characters. In order that they may admit of 

 easy application it is necessary that the characters thus combined shall 

 be neither too many nor too few. There are some families, such as the 

 Elateridffi, where the latter is the case 5 they are too homogeneous. 

 Others, even more numerous, as the Carabidse, for example, hold a just 

 medium in this respect; their species possessing a common basis of or- 

 ganization which is stable, or which varies but little. We here, there- 

 fore, have to deal with a restricted number of organs, which admit of 



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