64 AUTUMN AND WINTER 



inches in length, with a point projecting at one end : and 

 both have oblique stripes along the sides. The conspicuous 

 horn on the tail which is the badge of the hawk moth larvae 

 closely imitates the stem of the leaf; the rough shagreen-like 

 skin of the caterpillar mimics its colour and texture ; and the 

 stripes on the caterpillar's flanks reproduce the lateral veins 

 of the leaves. Only on a close examination is it likely to be 

 noticed that in the elm leaf the lines of the leaf and the stem 

 run parallel, while the horn of the caterpillar runs crosswise 

 to the stripes on its flanks. This mimicry may help to pro- 

 tect the lime hawk caterpillar from the hedgehogs, shrews, 

 moles and mice which forage along the surface of the ground 

 in the September nights. 



Similar concealment is afforded by their horns and stripes 

 and varying shades of green to the caterpillars of several of 

 the other species of hawk moth, which grow fat and descend 

 to earth about the same time. The privet hawk caterpillar 

 is a handsome great creature, nearly four inches long, of a 

 beautiful shade of apple-green, with mauve and white lateral 

 stripes. It feeds on holly and guelder and other shrubs, 

 as well as on privet ; and in spite of its large size, it is sur- 

 prisingly inconspicuous among the leaves. Its green blends 

 with the general shade of the foliage, its stripes imitate their 

 general markings, and the horn very fairly represents a spine 

 of holly or the privet leafs pointed tip. The resemblance 

 does not bear an exact comparison in detail ; it is not even 

 so close as that of the lime hawk to the withered elm leaves ; 

 but on the whole it is very effective. There is a specialised 

 resemblance, again, between the grey-green of the poplar 

 hawk caterpillar and the pale foliage of the poplars and willows 

 among which it feeds ; and the blue-green skin of the eyed 

 hawk caterpillar is surprisingly hard to detect among the 

 pale under sides of a spray of apple leaves, even though we 



