SOME OF THE "LOWER ORDERS" 187 



like the leaves of a book, so that the brightly-tinted, 

 and therefore conspicuous, area is concealed, as, for 

 example, in the " Red Admiral." With the Moths the 

 wings, while the creature is at rest, are held horizontally, 

 and it is the upper instead of the under surface which is 

 exposed, but the hind-wing is covered by the fore-wing. 

 The coloration is here very different ; for while the exposed 

 surfaces of the fore-wings are commonly soberly tinted, 

 the hind-wings may be quite glaringly coloured. These 

 bright colours are exposed only during flight, or during 

 moments of unusual excitement, as in the case of the Eyed 

 Hawk-moth. According to Weismann, this insect when 

 alarmed raises the fore-wings so as to expose the " eye- 

 spots " on the hind-wings, which, with the increased area 

 of the wings, impart a terrifying appearance to the body 

 to would-be assailants. This is as it may be, but for 

 the moment the feature to be insisted upon is that the 

 bright colours are almost invariably hidden when the 

 insect is at rest, and by quite different means, determined, 

 apparently, by the different carriage of the wings. Now, 

 according to some, bright colours are begotten by 

 strong hght, but in the Moth and Butterfly the surface 

 area of the wing which is most exposed is the surface 

 turned to the light during rest, and this is the least 

 coloured. The curious relation between this colora- 

 tion and the resting position is strikingly illustrated by 

 the case of one of the " small Blues " {Lyccence)^ cited by 

 Weismann. Herein the male, which has the upper surface 

 of the wings of a bright blue, rests in the position common 

 to Butterflies — with the wings raised and concealing the 

 bright colour — while the female, which has the upper 

 surface of a dull brown, rests with the wings expanded. 

 As, however, the concealed under surface is not brightly 



