208 TEXT-BOOK OF ENTOMOLOGY 



of the pupal state. The order of development of the colors in the 

 pupal wings has been observed by Schaeffer, Van Bemmelen, Urech, 

 Haase, Dixey, Spuler, and A. G. Mayer. The immature wings are 

 at first transparent and full of protoplasm. The transparent con- 

 dition of the wings corresponds to the period before the scales are 

 formed, and when they are full of protoplasm; they then become 

 whitish as the scales develop ; the latter are at first filled with pro- 

 toplasm, and afterwards turn whitish, being little hollow sacks filled 

 with air. After the protoplasm has completely withdrawn from the 

 scales, the blood of the pupa enters them, and then the coloring- 

 matter forms. (Mayer.) He adds that "about twenty-four hours 

 after the appearance of the dull yellow suffusion the mature colors 

 begin to show themselves. They arise, faint at first, in places near 

 the centre of the wings, and are distinguished by the fact that they 

 first appear upon areas between the nervures, never upon the 

 nervures themselves. Indeed, the last place to acquire the mature 

 coloration are the outer and costal edges of the wings, and the 

 nervures." 



The faint color of the scales gradually increases in intensity. 

 " For example, if a scale be destined to become black, it first becomes 

 pale grayish brown, and this color gradually deepens into black." 



Urech states that in Vanessa io first a white, and in V. urticce a 

 pale reddish hue, are spread over the entire wings, and then suc- 

 cessively arise other colors in the following order : yellow, yellow 

 to brown, red, brown and black. 



Spuler, however, claims that the differentiation of colors and 

 markings do not follow one another, but arise simultaneously, and 

 that his view is confirmed by Fischer. This may be the case with 

 the highly specialized and diversely marked butterflies, but certainly 

 taking the Lepidoptera as a whole the yellows and drabs must have 

 been the primitive hues, the other colors being gradually added in 

 the later more specialized forms. 



It is noticeable that the most generalized moths, such as the species 

 of Micropteryx, Tinea, Psychidse, Hepialidae (in general), etc., are dull 

 brown or yellow-drab without bars, stripes, or spots of bright hues. 

 These shades prevail in others of the more primitive Lepidoptera, 

 such as many bombycine moths, and they even appear to a slight ex- 

 tent in certain caddis-flies. The authors mentioned, especially Mayer, 

 whom we quote, claim that " dull ochre-yellows and drabs are, phy- 

 logenetically speaking, the oldest pigmental colors in the Lepidop- 

 tera; for these are the colors that are assumed by the hsemolymph 

 upon mere exposure to the air. The more brilliant pigmental colors, 



