THE FAERY YEAR 



and where they slept does not show that the usual 

 habit of sleeping head down is unessential. This 

 habit in some way ministers or has ministered to its 

 comfort or safety. Only how? It is conceivable 

 that the head in this position is less exposed to rain. 

 And yet the small heath does not sleep head down, 

 and is apparently not inconvenienced by the rain, 

 which shoots off the head, and leaves it dry and 

 snug. 



Masks of Colour and Form 



Few theories in natural history have received 

 more attention of late years than protective or 

 aggressive colour, " mimicry," and harmony with 

 environment. " When we see leaf-eating insects 

 green, and bark-feeders mottled grey ; the Alpine 

 ptarmigan white in winter, the red grouse the colour 

 of heather, we must believe that these tints are of 

 service to these birds and insects in preserving them 

 from danger." Since Darwin wrote thus, many 

 observations have been made, and conclusions drawn, 

 in support of the theory. To doubt this use of 

 colour to animals seems like inviting back chaos in 

 place of cosmos for, abandon the theory, and a world 

 of colour is straightway void of purpose, a muddle of 

 chance. So we all like the theory. Some, how- 

 ever, perceive plans to aid the wearer in every colour, 

 tint, shade, pattern. We may be sceptical of a good 

 many of the cases they cite in support of colour aid, 

 192 



