SOME SUGGESTIONS FOR THE STUDY OF INSECTS. 165 



generally well within its reach. It may spend its whole 

 larval existence on the same spot. The parent butterfly 

 on the other hand is equipped so as to disseminate the 

 species. It must go on depositing eggs upon food plants 

 in widely distributed areas and must find these plants 

 mainly by its sense of smell. This function is therefore 

 more acute in the adult.* 



The food of a caterpillar is solid, and biting jaws are 

 required to deal with it. A great deal must be eaten to 

 extract a small amount of nourishment. Since as already 



Fig. 64. The Tiger Moth. 



indicated the adult insect must travel some distance in the 

 performance of its prime function, it is important that its 

 body should be light and also that time should not be lost. 

 Lightness is gained and time saved in the change of diet 

 from solid to concentrated liquid food. Some insects 

 indeed do not feed at all in the winged state. 



The presence of wings and the disappearance of hind 

 body legs are to be explained with reference to the same 

 needs. The wings of the moth (as well as other parts of 

 the body) are covered with minute scales of different 

 colours, and it is the grouping of these* scales that yields 

 the colour pattern already described. Moths and butter- 



* The significance of the antennae in enabling the two sexes to 

 meet need not be raised with children, although it is a very import- 

 ant illustration of our point. 



