30 ORDEE, OP COLEOPTERA. 



habits than auy of the other orders of insects. Indeed this principle 

 of classification is of value just in proportion as such diversity exists; 

 and where it is very limited, as especially in the great order of Lepi- 

 doptera, it ceases to be available. Even in classifying the Coleoptera 

 upon this basis, and at the same time paying the necessary respect to 

 structural considerations, we are sometimes compelled to place insects 

 of similar food-habits in several different, and sometimes remote, tribes. 

 The wood-boring beetles, for example, constitute three distinct tribes, 

 designated as the saw-horned borers fBnprcstida'J ; the long-horned 

 borers fCerambi/cid<cJ, and the short-horned borers fScoh/tida'.J There 

 are likewise four distinct families of fungus-beetles, found respectively 

 in each of the four tarsal sections. But notwithstanding such instances 

 as these, the Coleoptera admit of a very interesting, useful, and, in the 

 main, natural classification in accordance with the nature of their food. 



As (;omi)ared with the other orders of insects the Coleoptera are sur- 

 passed only by the Lepidoptera in the extent of their injuries to culti- 

 vated crops ; and indeed they are so nearly equal to the latter in this 

 respect, that there may be a doubt which takes the i)recedence; and it 

 is true of either of these two orders, that, with the exception of the 

 other, it includes a greater number of injurious species than all the 

 other orders of insects combined. The great destructiveness of the 

 Jje])idoptera is readily explained by the nature of their food, nearly 

 all their larvte, commonly known as caterpillars, subsisting upon plant- 

 food, and mostly in a fresh and growing state. The Coleoptera, on the 

 contrary, embrace, in addition to the plant-eating species, extensive 

 tribes of predacious and scavenger beetles, which are indirectly of in- 

 calculable benefit to mankind. 



In studying the bearing of scientific upon practical entomology, noth- 

 ing j)erhaps is more important than to trace the connection of the ex- 

 ternal structure of insects with their halaits, and especially with the 

 nature of their food; since we are thus enabled, to a certain extent, to 

 determine the habits of an insect by simply observing the form and 

 structure of its visible parts. We are able to lay down some general 

 rules of this kind with respect to the Coleoptera, though most of them 

 are subject to important exceptions. In order not to give too much 

 space to this part of the subject, we will limit our observations to two 

 of the most important and i)rominent organs — the antenna;, and the 

 feet, or tarsi. 



All predaceous beetles have filiform antennae except the lady-birds or 

 CoccinellidfB. 



All the scavenger beetles have strongly clavate or knobbed antenna?, 

 except the short-winged scavengers or Staphylinida;, and these are only 

 partial exceptions, as many of them are known to be predaceous. 



