516 Mr. G. Lewis' supplementary note on the 



And the question of the relation between the more pal- 

 pable structure of a butterfl5^'s wing and the ribbed struc- 

 ture of the scales, which throw off the colour, evidently 

 opens up at this stage of the inquiry. For it seems very 

 possible that light is a powerful factor in modifying the 

 membranous anatomy of a butterfly, or even the harder 

 wing-case of a l»eetle. I am led to this remark especially 

 now, because I think pigmentary colouring in insects is 

 also due to solar-rays. 



In all varieties of man the palms of the hands and the 

 soles of the feet are not exposed, and, like the downy 

 feathers in birds, they are pale in all races. The colour- 

 ing substance in the cuticle of the negro is said to be 

 a protection against malaria, and as it has originated in 

 an insalubrious climate, which is fatal to Europeans, it 

 seems to me that the ungenial vapours of the swamps 

 in Africa is the condition of life which produces it. But 

 the domiciliary habits of man remove him somewhat 

 from the influences of those laws on which we can with 

 safety rely in our discussion of wild animals. 



In an early page of this paper it has been said that 

 nocturnal insects may be black because they are not in- 

 fluenced by the direct rays of the sun, and we have also 

 seen that Spanish Carahi, although as brilliant above as 

 the brightest of the Buprestidce, are black beneath. 

 Blackness to a nocturnal beetle is not more of a protec- 

 tive colour than scarlet would be, in fact even less ; a 

 scarlet geranium is notably one of" the first flowers at 

 twilight to be subdued in colour, and blackness in a 

 Blaps would make any stray specimen during daylight, 

 more conspicuous to a sparrow, than if it was banded 

 with blue and gold ; the intense blackness would, in fact, 

 sharpen the outline and render it visible at a long dis- 

 tance. If protective colour were beneficial to nocturnal 

 species, would not a large portion of the Tenebrionida be 

 grey or variegated ? In Heteromera, which roam at 

 night, we have more diversity of form perhaps than in 

 any other family of Coleoptera, showing that they have 

 been greatly subjected to modification ; so much so, that 

 we can almost think of them, as the nocturnal remnants 

 from ancestors in all the other families, yet they are 

 l)lack, and this means that when they can be seen they 

 are conspicuous. The most inconspicuous or protective 

 colour for any insect is grey or blue-grey, yet in a bright 

 clear mountain atmosphere in Spain, or in the glistening 



