COLOR IN ANIMALS 139 



There are instances in which insects are supposed to be 

 protected by an apparent resemblance to certain vertebrates. 

 Let me quote from Professor Poulton's delightful book The 

 Colors of Animals. 



" Mr. Bates describes a South American caterpillar which 

 startled him, and every one to whom he showed it, by its 

 strong resemblance to a snake, and it even possessed the 

 features which are characteristic of a poisonous serpent. 



" Equally interesting examples are to be found among 

 our British caterpillars. The brown (or occasionally green) 

 mature larva of the large elephant hawk moth (Chrczo- 

 campa elpenor) generally hides among the dead brown leaves 

 on the under parts of the stem of its food-plant, the great 

 willow herb (Epilobium hirsutuni) (Plate 78, A]. In this 

 position it is difficult to see, for it harmonizes well with the 

 color of its surroundings. It possesses an eyelike mark on 

 each side of two of the body rings (the first and second 

 abdominal segments), but these markings do not attract 

 special attention when the animal is undisturbed. 



" As soon, however, as the leaves are rustled by an 

 approaching enemy, the caterpillar swiftly draws its head and 

 the first three body rings into the next two rings, bearing 

 the eyelike marks. These two rings are thus swollen and 

 look like the head of an animal upon which four enormous, 

 terrible-looking eyes are prominent (Fig. 40). The effect is 

 greatly heightened by the suddenness of the transformation, 

 which endows an innocent looking and inconspicuous animal 

 with a terrifying and serpentlike appearance. I well remem- 

 ber the start with which I drew back my hand as I was going 

 to take the first specimen of this caterpillar I had ever seen." 



A good many different species of caterpillar show " terri- 

 fying " attitudes and motions. Poulton thus describes the 



