viii] THE LIFE-STORY AXD THE SEASOXS 89 



CHAPTER VIII 



THE LIFE-STORY AND THE SEASONS 



A NUMBER of interesting questions are associated 

 with the seasonal cycle of an insect's life-history. 

 In a previous chapter (iv. pp. 30, 34) reference has been 

 made to the contrast between the long aquatic life 

 of the larval dragon-fly or may -fly, extending over 

 several years, and the short aerial existence of the 

 winged adult restricted in the case of the may-flies 

 to a few hours. Here we see that the feeding activi- 

 ties of the insect are carried on during the larval 

 stage only ; the may-fly in its winged condition takes 

 no food, pairing and egg-laying form the whole of 

 its appointed task. A similar though less extreme 

 shortening of the imaginal life may be noticed in 

 many endopterygote insects. For example, the bot- 

 and warble-flies have the jaws so far reduced that 

 they are unable to feed, and the parasitic life of the 

 maggot (see p. 74) extending over eight or nine 

 months in the body of the horse or ox, prepares 

 for a winged existence of probably but a few days. 

 Again in many moths the jaws are reduced or vesti- 

 gial so that no food can be taken in the winged 

 state, as for example in the 'Eggars' (Lasiocampidae) 



