520 Mr. G. Lewis' supplementary note on the 



affinity, or one so remote, that the links of their relation- 

 shijD are lost. As there appears to be a photoplastic 

 l^rocess, so there appears to be an areo-plastic process. 

 Wild animals have most hair on those parts most ex- 

 posed to the weather, just as butterflies have the brightest 

 colours in parts most exposed to the sun and most pro- 

 tected from the elements. The colour of the lichens 

 agrees with that of the Aplecta tincta, because they are 

 both weather-beaten ; they seldom meet direct solar-rays, 

 and could not retain the impressions if they did, by 

 reason of their present structure. 



The form of the lichens is not wholly dissimilar to the 

 form of the scales of the Noctuce, because both, being in 

 the air, are free to develop in all directions. The under 

 wing of Cotocala nupta has flatter scales than the primary 

 wing, as the uj^per wing lies over it. I should expect to 

 find the costal margin of the under wing in Nocture freer 

 of scales and colour than in a GeometrcB, because the 

 costal margni of the primary wing of the first is robust, 

 and has nervures of thicker structure than the second ; 

 and it is the costal margin of the primary wing which 

 rests on the costal margin of the secondary wing. In 

 Geometra the hind portion of the primary wing, that 

 is the thinnest part of it, rests on the costal margin of 

 the secondary wing, and the protection afforded would 

 not be so complete. 



I exhibit here two butterflies, Morpko sp. and Nectaria 

 Jasonia ; one has raised nervures, or, to return to the 

 old simile of the sand,, here are lateral ridges of rock or 

 chalk, and solar-rays strike a surface unfitted to retain 

 their impressions. In the first the nerves are very fine 

 and delicate, and they permit the wings to close tightly, 

 and the smooth surface is beautifully concolorous. Some 

 butterflies are not brilliant in the wings near the base, 

 as, when the wings are in a position of rest, they do not 

 touch near the body ; the wings fit closest about their 

 centre, and this is where bright colour first appears, or in 

 the centre of the spaces between the nerves. 



Examine a specimen of Scdpinx superha, male ; this 

 butterfly appears bright in the upper wing just in the part 

 which is in rest most protected from the atmosphere. 

 There is a good wide margin on all sides of it without 

 colour. And then the nerves seem to confine certain 

 spots, which appear spreading, to the centre of the spaces 

 between them, for the nerves meet and press close, and 



