334 Studies in the Theory of Descent. 



its possessor in the highest degree conspicuous by 

 strongly contrasted and brilliant colouring, so that 

 it might be anticipated that perfect eye-spots in 

 certain unpalatable species would lose their original 

 meaning, and instead of serving for terrifying be- 

 come mere signals of distastefulness. This is 

 perhaps the case with Chcerocampa Tersa (Fig. 35), 

 the numerous eye-spots of which make the insect 

 easily visible. Without experimenting on this 

 point, however, no certain conclusion can be 

 ventured upon, and it may be equally possible that 

 in this case the variegated ocelli with bright red 

 nuclei resemble the blossoms of the food-plant 

 (Spermacoce Hyssopifolia). 7 I here mention this 

 possibility only in order to show how an inherited 

 form of marking, even when as well-defined and 

 complicated as in the present case, may, under cer- 

 tain circumstances, be turned in quite another 

 direction by natural selection, for the benefit of its 

 possessor. Just in the same manner one and the 

 same organ, such, for instance, as the limb of a 

 crustacean, may, in the course of phyletic develop- 

 ment, perform very different functions first serv- 

 ing for locomotion, then for respiration, then for 

 reproduction or oviposition, and finally for the 

 acquisition of food. 



7 [The eye-spots on Ch. Nerii have thus been supposed by 

 some observers to be imitations of the flowers of the periwinkle, 

 one of its food-plants. See, for instance, Sir John Lubbock's 

 "Scientific Lectures," p. 51. R.M.] 



