ADAPTATIONS TO HAUNTS AND SEASONS 301 



perhaps semng as a protection. Not until the sprouting 

 of the young leaves in spring-time affords promise of food- 

 supply do the little bristly caterpillars come out of their 

 egg-shells. Hard-shelled winter eggs usually oval in shape 

 are especially characteristic of the plant-sucking aphids or 

 greenfly. These are laid in the autumn on the twigs of the 

 food-plant by the females of the last generation of the year 

 after pairing with males of the same brood. The black 

 shining eggs of the apple aphids are, despite their small 

 size, almost conspicuous on the bare branches through the 

 winter ; from them are hatched in spring the " stem 

 mothers " earliest of the virgin generations. Yet the normal 

 restriction of the virgin greenfly to the spring and summer 

 months is not always observed. The well-known Woolly 

 Aphid of the apple {Schizoneura lanigera), the original winter- 

 ing stages of which are eggs on elm trees, often carries on 

 successive virgin generations through the cold season, the 

 insects enduring because they are protected by their dense 

 waxy secretion, and because they often shelter in deep 

 cracks and crevices of the bark of the apple branches, or 

 even penetrate into the core-cavities of such apples as are 

 open at the " eye " end of the fruit. 



A large number of insects of different orders winter as 

 larvae, and among these there is great variety as to the 

 particular larval stage — whether early, median, or late — 

 that carries the race over the cold season. Insects with a 

 larval life prolonged over several years must obviously survive 

 several winters at successive periods of their lives, and such 

 generally live and feed in situations which are not subject 

 to great changes of temperature. Thus the long-lived 

 aquatic larvae of mayflies and dragon-flies continue from year 

 to year in the relatively equable temperature of their 

 freshwater home. Among beetles the " wireworm " grubs 

 of click-beetles and the heavy larvae of chafers are feeding 

 on roots in the soil if the weather be mild, but they may 

 burrow deeply in order to escape the effects of severe frosts. 

 Among larvae of Lepidoptera, the large slow-growing cater- 

 pillars of the Goat Moth (Cossus) pass the winter in their 



