The Origin of the Markings of Caterpillars. 307 



Ligustri in his possession this autumn, some of which had been 

 found on lilac and others on laurestinus, and he states that all 

 those on the latter plant had the ground-colour distinctly darker 

 than in those feeding on lilac. I learn also from Mr. W. Davis, 

 of Dartford, that he found a number of these larvae this year 

 feeding on ash, and that they were all differently coloured to 

 those found on lilac or privet, being of a more greyish-green. 

 Another case of colour-variation in larvae is that Emmelesia 

 Unifasdata, specimens of which I have recently had an oppor- 

 tunity of examining, through the courtesy of Mr. W. Davis. 

 This species feeds on the seeds of a species of Bartsia when 

 the capsules are in various stages of growth, and (omitting 

 details of marking) those caterpillars found on the green cap- 

 sules were green, whilst those on the brown capsules were of a 

 corresponding colour. 



On the whole I am inclined to believe that sufficient import- 

 ance has not hitherto been given to phytophagic variability as 

 a factor in determining larval coloration, fc and a large field 

 for experimental investigation here lies open for future work. 

 The obscure chemico-physiological processes which may 

 perhaps be shown by such researches to lead to phytophagic 

 variation, cannot, I am persuaded, produce any great divergence 

 of character if unaided \ but when such causes of variability play 

 into the hands of natural selection variations of direct pro- 

 tective advantage to the species, we can easily see that this all- 

 important agency would seize upon and perpetuate such a 

 power of adaptability to a variable environment. (See Proc. 

 Zoo. Soc. 1873, p, 158, and "Nature," vol. xiv., pp. 329 and 

 330. R.M.] 



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