166 SOME SUGGESTIONS FOR THE STUDY OF INSECTS. 



flies are classed in an Order of Insects termed Lepidoptera, 

 which means " scaly winged." 



Very frequently the colours and patterns produced by 

 these scales have protective significance. We may note 

 here just one general point. In those Lepidoptera which 

 rest with the upper sides of the wings exposed (moths) the 

 brightest colours are concealed and the exposed parts 

 frequently harmonise with the normal background (e.g. a 

 tree trunk). In those Lepidoptera which rest with the 

 wings erect over the back so that their under sides are 

 exposed, the showy pattern is on the upper (i.e. the hidden) 

 side (butterflies). 



ORDERS OF INSECTS. 



In our previous study we became familiar with certain 

 general facts of insect structure. As a contribution 

 towards the definition of an insect let us enumerate the 

 more important of these. 



(1) The body is divided transversely into segments. 



(2) Three divisions (constituting groups of segments) 



are recognisable in the adult, viz. Head, Thorax, 

 and Hind Body or Abdomen. 



(3) The head carries one pair of feelers or antennae. 



(4) There are three pairs of legs upon the thorax (one 



pair to each of its segments). 



(5) Wings are usually present, but not invariably 



(Fig. 65). 



In a revision lesson all these points should be verified on 

 a new type, e.g. a Bee, Cranefly, or Butterfly, or Grass- 

 hopper. In some types, e.g. Flies, the antennae are small, 

 but the other characters are readily made out. 



The variety of form amongst insects is very great. 

 Hence the group is subdivided into Orders, and of these 



