PROTECTIVE COLORATION. 89 



and j)atclies of mildew are varied in extent and position — so the 

 under sides of the wings of the Kallima show a considerable 

 range of diversity. This instance is perhaps the most 

 striking case of resemblance to the environment that has 

 been yet described and illustrated (see plate). 



Protection afforded by Resemblances of this kind chiefly efiicacious 

 against Vertebrate Animals. 



As a matter of a fact, are animals concealed by their 

 " l^rotective resemblances " from their foes ? This is a question 

 which really cannot be answered in many cases ; sufficient data 

 upon which to found a reply are not forthcoming. A few 

 points, however, bearing upon the matter may be- noted. No 

 doubt Mr. Poulton is quite right when he says that no species, 

 however perfectly it is concealed by these means, can wholly 

 escape. If this means of protection and that afforded by 

 warning colours were entirely successful, insect-eating birds 

 would disappear altogether for lack of food. And besides, 

 caterpillars — to limit ourselves to that class for the present — 

 have other enemies besides birds. They are eaten by monkeys, 

 lizards, frogs and toads, and by other insects, such as wasps; 

 Ichneumon flies deposit their eggs in them, and thus ultimately 

 destroy them. It is just as important for a caterpillar to be 

 protected from these Hymenoptera as from birds, which are 

 perhaps the chief enemies among Vertebrates — in this country 

 at any rate. 



In discussing these and similar questions, there is always too 



great a tendency to endow animals with senses exactly similar 



to those possessed by ourselves. This tendency is, of course, 



more dangerous when we are dealing with the lower animals. 



Mr. Plateau's experiments in the vision of Arthropods* are thus 



* Dr. Sharp's most useful abstract is in Tran". Eutom. Sncidij, London, 

 for 1889. 



