ADAPTATIONS TO HAUNTS AND SEASONS 303 



{Lasiocampa ruhi) becomes fully grown before it hibernates, 

 and does not feed after awakening to fresh activity in the 

 spring, though it drinks water and suns itself before spinning 

 its cocoon and pupating. The destructive caterpillars of 

 the Codling Moth {Carpocapsa pomonella) after feeding 

 within young apples, seek shelter under loose pieces of bark 

 and spin their cocoons there, often as early as midsummer ; 

 yet they remain unchanged through the winter and do not 

 pupate until the succeeding spring. A prolonged rest and 

 hibernation in the final larval stage is characteristic also of 

 many sawfly caterpillars, which spin their cocoons in 

 autumn, at or below the surface of the ground and wait for 

 the return of spring to assume the pupal stage. Among 

 the Burnet Moths (Zygaena) H. BurgefT (19 10) has shown 

 that the caterpillar hibernating in its fourth stage assumes 

 a specially modified form ; after the last moult of the year 

 it appears with an abnormally small head and dull-coloured 

 body, and then passes into the winter sleep, after which it 

 drinks, swells to a larger size, and moults again, appearing 

 in its final stage with the usual bright yellow and black 

 livery of its group. The winter habits of such Owl Moths 

 (Noctuidae) as the Turnip Moth {Agrotts segetum) and its 

 allies, are especially interesting on account of the plasticity 

 in adaptation that they exhibit. The dull, brown- winged 

 adults are flying in the June evenings and their greyish 

 caterpillars feed on various herbs of the field, usually 

 burrowing in daytime and eating shoots at the ground level 

 by night. Thus the habit of burrowing for shelter and 

 food is normal to these larvae, and they carry it on through 

 the winter, except that during hard frosts they go deep into 

 the soil. Most of the segetum caterpillars in our countries 

 remain thus intermittently active through the winter and 

 pupate in spring in an earthen chamber in the soil. But a 

 minority of them grow faster than the rest, so that they are 

 ready for pupation in early autumn, and the moths of a 

 partial second brood emerge in September. The offspring 

 of these join the older wintering larvae in the soil and grow 

 fast enough to complete their transformation about the 



