NO. 7 PROTECTIVE ADAPTATIONS McATEE 53 



yellow Papilio tiiniiis, which in all probability obtains protection from 

 its general resemblance to P. philenor." (Darwinism, p. 248, 1896.) 



Mimicry of another order of insects, the Hymenoptera, is shown 

 1)V many of the clear-winged moths (Syntomidae and Sesiidae) as 

 adults ; and of black-and-yellow ringed larvae, it is said they gain 

 great advantages from resemblance to the justly respected appearance 

 of hornets and wasps. 



The majority of adults of Lepidoptera, especially the moths, exhibit 

 in greater or less perfection what is called cr3'ptic coloration, that is 

 resemblance to details of the environment, exemplified by the species 

 that are inconspicuous on bark, old leaves and the like. This style of 

 protective adaptation also is attributed to many larvae and pupae. On 

 this topic Poulton says : " There is no better instance of special pro- 

 tective resemblance than that afforded by the larvae of Geometrae, 

 ' stick caterpillars ' or loopers as they are often called. These cater- 

 pillars are extremely common and between two and three hundred 

 species are found in this country [Great Britain] ; but the great 

 majority are rarel}^ seen because of their perfect resemblance to the 

 twigs of the plants upon which they feed." (Poulton, E. B., The 

 colours of animals, p. 26, 1890.) 



This idea is pushed to an extreme by another author as shown by 

 the following quotation relating to the caterpillar of " a geometrid 

 moth. In the larval state the insect bears a very close resemblance 

 to a twig. Its habit of clinging to a real twig with its posterior ' legs ' 

 and allowing the body to swing out, adds to the illusion. The head 

 of the caterpillar resembles a leaf bud, while in color the entire 

 creature is an exact counterpart of a rough apple twig, the plant upon 

 which it naturally feeds. Thus complete immunity is secured from the 

 attacks of birds and all enemies which depend chiefly upon sight." ' 

 (Howes. Paul Griswold, Insect behavior, pp. 164-165, 1919.) 



Adaptations of caterpillars supposed to repel enemies, which have 

 received the most attention from writers on the subject, include : 

 armatures of hairs or spines, repugnant odors, warning colors, and 

 terrifying attitudes, in addition to various special resemblances. 

 Among the latter, Howes considers especially remarkable those that 

 " rely for their protection upon their mimicry of the excreta of birds. 

 I have been completely fooled by these larvae on more than one 

 occasion. They frequently rest in the center of a green leaf and while 

 conspicuous, never suggest a living insect to the uninitiated. In color, 

 the upper and lower portions of the body are dark chocolate brown. 



' See pages 56 and 85 for the facts as to immunity of loopers. 



