164 A BOOK OF INSECTS 



campa elpenor and C. porcellus) gain protection in a 

 similar way. When quietly resting among the leaves of 

 their food-plant, they are concealed by their brown — more 

 rarely green — colouring. But when alarmed by a rustling 

 of the surrounding herbage, the caterpillar suddenly draws 

 back its head and the first three (or thoracic) segments of 

 its body into those behind. As a result, the front part 

 of its body becomes swollen, and looks like the head of 

 an animal, upon which four enormous, awe-inspiring eyes 

 are prominent. The effect is greatly heightened by the 

 suddenness of the transformation, an inconspicuous 

 creature being changed without warning into the sem- 

 blance of a grotesque monster. This description applies 

 to the caterpillar of the large elephant hawk-moth. In 

 the case of the smaller species, the posterior pair of 

 eye-spots, though present, is not very conspicuous ; so 

 that the caterpillar, in its terrifying attitude, appears to 

 have only two eyes. Professor Poulton tells us that 

 " such caterpillars terrify their enemies by the suggestion 

 of a cobra-like serpent ; for the head of a snake is not 

 large, while its eyes are small and not specially con- 

 spicuous. The cobra, however, inspires alarm by the large 

 eye-like ' spectacles ' upon the dilated hood, and thus offers 

 an appropriate model for the swollen anterior end of the 

 caterpillar with its terrifying markings. It is extremely 

 interesting that the caterpillar should thus mimic a feature 

 which is only deceptive in the snake itself." 



A like policy of bluff is adopted by certain adult 

 insects, such as the well-known devil's coach-horse 

 {Ocypus olens), which, when alarmed, assumes an attitude 

 of menace, suggestive of a scorpion, although it possesses 

 no sting. But the eye-like spots upon the wings of many 

 butterflies and moths, as well as the so-called " tails " of 

 the hind-wings, are believed to benefit their owners by 



