26 BUTTERFLIES 



enon, but these bodies are relatively so small that counter- 

 shading plays but a little part in the general display. 



Upon the outstretched membranes of the butterflies' 

 wings Nature through the long ages of development has 

 painted a great variety of pictures. Those which tend to 

 protect the insect by concealment amid its surroundings are 

 most commonly spread on the under surface of the wings. 

 Especially is this true in the case of those species which 

 pass the winter as adults or which have the habit of resting 

 upon the bark of trees, the sides of rocks, or the surface of 

 the ground. We here find some of the most interesting 

 examples of obliterative coloring that occur in nature. 

 Some butterflies have taken on the look of tree bark, 

 others the sombre appearance of weathered rocks, while 

 still others are painted with the images of flowerets and 

 their stems. 



Dazzling and Eclipsing Colors 



Many of the butterflies, especially the Angle-wings, 

 which are marked on the under surface in various pro- 

 tective colors, are admirable examples of that phase of 

 animal coloring which is spoken of as dazzling coloration. 

 This is apparently one of the most important protective 

 devices to be found in Nature and the validity of it is now 

 generally conceded by naturalists. One phase of it, which 

 may be called eclipsing coloration, seems to have been first 

 definitely formulated by the late Lord Walsingham, a 

 famous English entomologist who enunciated it in an ad- 

 dress as president of the Entomological Society of London. 

 The most significant paragraphs in that address were these: 



" My attention was lately drawn to a passage in Herbert 

 Spencer's * Essay on the Morals of Trade.' He writes: 



