THE COLORATION OF ANIMALS 75 



the dry leaves on the ground in the light woods which it is fond of 

 frequenting. 



Our gayest diurnal butterflies, the species of Vanessa, all have the 

 under surface of a dusky colour, sometimes passing into a blackish 

 brown, as in the peacock-butterfly, Vanessa (v. io), sometimes more 

 into greyish brown, or brown-yellow, or reddish brown. They are 

 never simple colours, but always consist of mixtures of different 

 colour-tones — indeed, there is often a complex mingling of many 

 colours, as grey, brown, black, white, green, blue, yellow, and red, 

 made up of dots, strokes, spots, and rings, into a wonderful and very 

 constant pattern, which, taken as a whole, has the effect of being 

 uniform, and harmonizes with the soil, or with the highway, on 

 which the species loves to settle, with much greater accuracy than 

 a monochrome grey or lirown would do. When the 'painted lady' 

 {Vanessa cardui) settles on the ground it is hardly distinguishable 

 from it, and this species in particular has a preference for settling on 

 the ground. Other species of Vanessa, such as the peacock and the 

 Camberwell beauty (Vanessa antiopa), are underneath of a dark 

 blackish grey, or even black ; when resting they press themselves 

 into the darkest corners and crevices, and are thus most effectively 

 secured from discovery. 



Many diurnal Lepidoptera, on the other hand, especially the wood- 

 buttei-flies of the family Satyridas, have the habit of resting on the 

 trunks of trees, as Satyrus proserpina does on the great beech-trunks 

 of the forest clearings. These large butterflies, coloured conspicuously 

 on the upper surface in deep velvety black and white, are marked on 

 the under surface exactly to match the whitish bark of the great 

 beech, covered over with white, grey, blackish-brown, and yellow spots, 

 and the butterfly whose flight one has just been carefully following 

 disappears as it suddenly alights on such a tree-trunk. As I have 

 already stated, the protective colour only extends over as much of the 

 insect as is seen when it is at rest. As the anterior wings are folded 

 far back between the posterior ones, the pi^otective colouring is limited 

 to the whole surface of the posterior wing, and the tip of the anterior 

 one, as far as that is visible in the resting attitude ; the protectively 

 coloured area is somewhat sharply bounded, and it is often of very 

 diflerent extent in quite nearly allied species, according to whether 

 the species folds the anterior wing far back or not. Thus in our 

 common small tortoiseshell-butterfly ( Vanessa uHicoi) the protective 

 area is considerably wider than in the large tortoiseshell ( Vanessa 

 2}olychloros), much as the two resemble each other in other details. 



This harmony between the wing tips and the posterior wings is 



