INSECTS. 183 



attacked, one can distinguish between Root-destroyers, such as the mole- 

 cricket and the cockchafer grub ; Wood-borers, comprising the larvae of 

 wood-wasps, cervicorn beetles, some bark-beetles, and goat-moth cater- 

 pillars ; Bark-beetles, and some weevils, which often, both as beetle and 

 larva, either destroy the cambium and the sapwood, or else hollow out 

 the pith in young shoots (e.g., some Hylesinini and Tortricidce) ; Bud- 

 and Leaf-destroyers, including other weevils, most moth- and sawfly- 

 caterpillars, leaf-beetles, cockchafers, and some plant-lice (e.g., Larch 

 aptera) ; Producers of Deformities and Malformations on foliage, shoots, 

 and fruits, as gall-wasps, gall-midges, and plant-lice (e.g., Spruce aphis). 



But the now generally accepted scientific classification into 

 orders is as follows : 



A. With complete metamorphosis (egg, larva, pupa, adult). 



I. Coleoptera ("shield- wings") or Beetles, having 2 pairs of wings, 

 the front pair being hard and horny (elytra], and forming 

 shields for protecting the soft membraneous hind-pair used 

 in flying ; mouth for biting. 



II. Lepidoptera ("scale- wings") or Butterflies and Moths, 1 having 2 

 pairs of flat membraneous wings more or less completely 

 covered with flat scales ; mouth biting for larva, and sucking 

 for adult. 



III. Hymenoptera (" skin-wings ") or Sawflies, Wasps, Bees, and 



Ants, having 2 pairs of wings, all membraneous, with few 

 wing-cells, and a distinct dark area along the upper border ; 

 mouth for biting, or for both sucking and biting. 



IV. Diptera ("two- wings") or Flies, having only 1 pair of mem- 



braneous wings attached to mesothorax, the hind pair being 

 only rudimentary and aborted into two small stalked knobs 

 (haltcres) used as poisers or balancers ; mouth biting for larva, 

 and sucking or piercing for adult. 



1 Butterflies have feelers always ending in a club-like knob, are mostly 

 diurnal in habit, and are of little or no importance to the forester ; 

 whereas moths with feelers variable in form, but never ending in a 

 knob, are usually more or less nocturnal in habit, and are often very 

 destructive. 



