CHAPTER II. 



INSECTS. 



XNSECTS are easily distinguished from the other jointed animals by many salient characters. 

 -L They have one pair of antennae, two large compound eyes, composed of a great number 

 of facets, and sometimes one, two, or three simple eyes pJaced on the crown or front of 

 the head. In its adult condition an insect is composed of three different parts, wdiich can 

 be most readily noticed in a w-asp. There is the head, with the antennae, and mouth-parts; 

 the thorax, to which one or two pairs of wings are attached above, and three pairs of legs 

 below; and the abdomen. Insects breathe through openings, called " stigmata,'' in the sides of 

 the thorax and abdomen. They never possess more than six legs in the perfect state, the 

 abdominal legs present in caterpillars, etc., disappearing in the adult condition. They generally 

 pass through what is called a " metamorphosis," — four different stages of life, called respectively 

 egg ; larva or caterpillar ; pup)a, nymph, or chrysalis ; and imago, or perfect insect. 



Insects are divided into several large sections, of which the following seven are the most 

 imp)ortant, and many entomologists prefer to include all insects under them : — 



Sheath-winged Insects, or Beetles ; Straight-winged Insects, or Earwigs, Cockroaches, 

 Soothsayers, Stick-insects, Crickets, Grasshoppers, and Locusts ; Nerve-winged or Lace-winged 

 Insects, or Dragon-flies and their relatives ; Stinging Four-winged Insects, or Ants, Bees and 

 Wasps, and their allies ; Scale-winged Insects, or Butterflies and Moths ; Plalf-winged Insects, 

 ■or Bugs and Frog-hoppers ; Two-winged Insects, or Flies. 



We proceed to notice these orders separately. 



SHEATH-WINGED INSECTS, OR BEETLES. 



BY THE REV. THEODORE WOOD, F.E.S. 



Beetles are distinguished from most other insects by the fact that the front wings are 

 not employed in flight, but are modified into horny sheaths, which cover and protect the 

 lower pair while not in use. This arrangement, however, is also found in the Earwigs as well 

 as in the so-called '' Black-beetle " and its allies, and it is to be noted that the wing-cases of 

 beetles lie evenly side by side together when the wings are folded, while the folding of the wings 

 themselves is transverse as well as longitudinal. The number of species 



is very great, upwards of 100,000 ■ having already been described, of 



which about 3,400 ha\-e lieen taken in the British Islands. 



The order is again divided into ' several smaller groups, first among 



which stand the predaceous beetles ^, of the land. Of these the common 



English Tiger-beetle is a familiar ~, W example. It is found on sandy and 



peaty heaths, and may be known )_J - _[ at once by its bright green wing- 



cases, marked wdth white sjwts, and ^^'JKIl ^ ^^^^ metallic blue of the abdomen. 



The legs are coppery. It flies with great ' f^r) swiftness in the hot sunshine, taking 



to wing as readily as a blue-bottle fly, 1 ( and feeds entirely upon other insects. 



Another representative of the ' \. group is ricli golden green in colour, 



with coppery reflections. It is only . _' . an occasional visitor to Britain, 



but abounds in France and Germany, ^K^&'L„!^xfpa!i:'. ^yheve it feeds upon the caterpillars 



of the famous Processionary jNIoth, tigek-beetle. =^^^1 is largely instrumental in 



checking their ravages in the great Tho coiourin.!; of this oak forests. 



Familiar to almost all is the insect is biight g.een .nth Purple Grodnd-beetle, so plentiful 



white markings iind coppery • 1 , ■ .._ j_i ii i 



in gardens, and easily recognisable isgs. nj tte violet margin to the black 



esi 86 



