PROTECTIVE COLORATION. 101 



by burrowing into the sandy soil upon which their food-plant 

 was placed. Scudder also says that the larva of the GEneis, 

 already referred to as being possibly a lichen-feeder, feeds by 

 night and hides itself by day under stones. Mr. Scudder never 

 .succeeded in finding these caterpillars during the day except 

 under stones. Now, in these cases the colour obviously does not 

 matter; if, therefore, the longitudinal striping is kept up by 

 -constant selection on account of its utility, and has no other 

 signification, we might expect that in these two species, and in 

 others with similar habits, the cessation of natural selection 

 would have permitted the high standard required in the other 

 cases to be lowered, perhaps, even, as has been suggested in 

 the case of the cave-animals, the colours being useless to their 

 possessors, might have disappeared altogether, but they have 

 not ; the caterpillar of the " Grayling " is a typical Satyrid 

 caterpillar. 



As an alternative suggestion to modification of coloration to 

 suit environment, may not we suppose sometimes a change of 

 environment to fit in with colour ? This is, perhaps, a crude 

 way of stating it, as it suggests a deliberate picking and 

 choosing on the part of the caterpillar of a plant or locality 

 best adapted to the concealment of its otherwise conspicuous 

 livery. (See, however, the case of the black moth quoted on 

 p. 113.) Prof. Drnmrnond * suggests how easy it is to produce 

 changes of structure, which free the animal so changed from 

 any need of alteration of habit. "A few daubs of colour, a 

 little modelling of thorax and abdomen, a deft turn of antenna 

 and limb, and the thing is done," he says. If natural selection 

 chooses the easier path, which we must obviously assume to be 

 the case, a change of habit will be often much easier. There 

 are plenty of examples of change of habit in the animal 



* " Tropical Africa." 



