80 THE COLOURS OF ANIMALS 



adventitious in origin, having been derived from the 

 chlorophyll of the leaves ; it is, however, much modi- 

 fied in constitution by the time it reaches the blood. 

 The green colouring matter passes from the blood 

 into the cells of the surface of the body in many 

 caterpillars, but is re-dissolved in the blood of the 

 chrysalis. It is then made use of, in certain species, 

 to tinge the eggs, and, after this, is absorbed into the 

 body of the young larvae which afterwards hatch from 

 them, protecting them with a green colour before they 

 have had time to acquire fresh chlorophyll from the 

 leaves. The passage of an adventitious colouring 

 matter on into a second generation is a very remark- 

 able phenomenon. There does not, however, seem to 

 be any doubt about its occurrence in certain species 

 (e.g. Smerinthus ocellatus) , l and I have a good deal of 

 unpublished evidence on the subject. 



1 See ' Proceedings of Physiological Society,' pp. xxv and xxvi, 

 in Journal of Physiology, vol. viii. 1887. 



