PKOTECTIVE COLORATION. 97 



mode of life may encourage the growth of these vegetable 

 parasites, which could not gain a footing npou the bodies of 

 more active animals. 



Protective Coloration the Prevailing Device among 

 Leaf-feeding Caterpillars. 



The majority of the caterpillars of the Lepidoptera are pro- 

 tectively coloured ; it is the rule, for instance, with the extensive 

 families of the Noctuae, the Geometrje and the Tortrices ; there 

 are exceptions to this rule, as to every rule: for example, the 

 larvae of the Acronyctides, the Dagger moth and its allies, 

 including the " Merveil du Jour " ; these larvte are usually hairy 

 and brightly coloured; this exception, however, may possibly 

 be explained as due to affinity : the larvfe closely resemble the 

 brightly or at least conspicuously coloured and hairy larva? of 

 the Boiubyces; and this group of Noctuae are sometimes classed 

 apart from the rest as Bombycoidea, a term which gives ex- 

 pression to this view. On the whole, it seems more profitable 

 to a caterpillar to adopt protective resemblance to its sur- 

 roundings as a means of escaping its foes ; at any rate, this 

 is what actually occurs. " The main purpose in life of a 

 caterpillar," says Mr. Scudder, '• next to feeding, is not to be 

 seen."" Even some larva' which are commonly regarded as 

 exhibiting warning colours are by no means conspicuous, 

 particularly if they feed among flowers, or upon low-growing 

 plants in situations where there is a varied vegetation and 

 abundance of flowers. Larvic, as well as other animals which 

 have not a very marked protective resemblance to any special 

 object, or have not a colour which is in general harmony with 

 the environment, are nevertheless by no means invariably 

 conspicnous. 



