[ 492 I 72 



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, desig- 

 nated as the saw-horned borers (Buprestidce) ; the long-horned borers 

 {Ceramhycidce) ; and the short-horned borers (Scolytidw). 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 compared with the other orders of insects the Coleoptera are sur- 

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

 ted crops ; and indeed they are so nearly equal to the latter in this re- 

 spect, that there may be a doubt which takes the precedence ; 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 Lepidop- 

 tera is readily explained by the nature of their food, nearly all their 

 larvae, commonly known as caterpillars, subsisting upon plant-food, and 

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

 embraces, in addition to the plant-eating species, extensive tribes of 

 predaceous and scavenger beetles, which are indirectly of incalculable 

 benefit to mankind. 



In studying the bearing of scientific upon practical entomology, 

 nothing perhaps is more important than to trace the connection of the 

 external structure of insects with their habits, 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 prominent organs, the antennae, and the 

 feet, or tarsi. 



A ll predaceous beetles have filiform antennae except the lady-bugs or 

 CoccineUidae. 



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

 except the short- winged scavengers or Staphylinidic. 



All the leaf-eating beetles have filiform or nearly filiform antenna;, 

 except the herbivorous Lamellicorns fliuteUdce and Melolonthida'.J 



All fungus-eating beetles have the antennae more or less strongly cla- 

 vate. 



The feet of the Coleoptera are of two principal kinds ; first, simple 

 feetf in which the joints are slender, and of about the same width 



