VI. Biology. 6. Protective Adaptations. 



71 



Other means of protection are of a purely defensive nature, 

 and here there is a great diversity. Many animals try to escape 

 danger hy flight, and many weak and defenceless fonns have 

 remarkable powers in this direction {e.g. Antelopes). Others save 

 themselves by hiding. Many offer resistance in the shape of a 

 specialised protective covering (a prickly skin, a stiff coat of mail). 

 Not a few Insects are characterised by a repulsive taste or odour, and 

 by this keep the enemy at a distance ; many animals are protected, 

 whether in motion or at rest, by their resemblance to their sur- 

 roundings (protective resemblance) ; many, on account of their green 

 colour, are difficult to distinguish from their food-plant ; many, again, 

 are concealed by the leaf -like appearance of the wings or other parts : 

 the most delusive resemblance is perhaps found in some Indian 

 diurnal Butterflies (Kallima) which can scarcely be distinguished 



Pig. 43. Two specimens of a Kallima 

 settled, with closed wings, between withered 

 leaves. — After Wallace. 



Fig. 44. Two looper oaterpillers (Qeo- 

 meira betularia). 



from the dry leaves of the trees or shrubs whereon they rest with 

 folded wings. Among European Lepidoptera, a Bombyx (Gastropacha 

 quercifolia) also exhibits a remarkable similarity to dry leaves. Other 

 Insects are like withered twigs, e.g. some Looper-caterpillars (Fig. 44), 

 which extend motionless from a branch, attached only by the hinder 

 end. 



It seems specially remarkable that some animals which are 

 protectively modified have come to resemble, externally, others 

 which are from some cause unpleasant to their enemies, and 

 therefore, are comparatively unmolested (mimicry). In South 

 America, for instance, there lives a group of Butterflies (the Heli- 

 conidse), poor fliers, with conspicuous colouring but with so unpleasant 

 a smell, that they are rejected by Birds ; certain other Butterflies, 

 living with these, but not possessing their odour, are remarkably like 



