HETEROMEROUS GROUND-BEETLES. 
121 
vate aud moniliforru antennae, and their uniformly dark or black colora- 
tion. The above name of Latreille, meaning black-bodied , is expressive 
of this character. As a general rule they are rather large beetles, many 
of them being above the medium size, aud 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 larvae of which are some- 
times seriously injurious to flour and meal of different kinds. The larvae 
of a few species have been found in rotten wood. All the known larvae 
are very similar in form aud structure, aud are well represented by the 
common meal-worm which is the larva of the Tenebrio molitor, Linn. 
This is a loug, 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 larvae 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- 
brionid®, in which he also includes the fungus-beetles ( Diaperidee ). In 
this course he has been followed by our own distinguished coleopterist, 
Dr. John L. LeConte, and more recently by Dr. George H. Horn, of 
Philadelphia, who has published an elaborate monograph of the N. 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 
Elaterid®, where the latter is the case ; they aro too homogeneous. 
Others, even more numerous, as the Cara bid®, 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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