MAYER: COLOR AND COLOR-PATTERNS. 227 



pujja. The pupal blood of the Saturnidae is a j^roteid substance 

 containing egg albumen, globulin, fibrin, xanthophyll, orthophos- 

 phoric acid, iron, potassium, and sodium (p. 176). 



(4) In Callosamia promethea and Danais plexippus the pupal 

 wings are at first perfectly transparent, then white, then impure 

 yellow, excepting upon those portions which are destined to remain 

 white in the mature wing. The mature colors then begin to appear 

 near the central areas of the wings and beticeen the nervures. Last 

 of all, the nervures themselves become tinged with the mature 

 colors. The central portions of the wings acquire their mature 

 colors before the outer and costal edges, or the root of the wing 

 adjacent to the body (p. 178, Plate 3). 



(5) The white stage in the development of color in the pupal 

 Avings represents the condition in which the scales are perfectly 

 formed but lack the pigment which is destined to be introduced 

 later (p. 178). (See, also, Mayer, '96, p. 230.) 



(6) Dull ocher-yellows and drabs are, phylogenetically speaking, 

 the oldest pigmental colors in the Lepidoptera. The more brilliant 

 colors, such as bright yellows, reds, and pigmental greens, are 

 derived by complex chemical processes and are, phylogenetically 

 speaking, of recent appearance (p. 178). (See, also, Mayei', '96, p. 

 2.32.) 



(7) While the number of species of Papilio in South America 

 is 9 times as great as in North America, the number of colors which 

 they display is only twice as great. Hence the greater number of 

 colors displayed by the tropical forms may be due simpl}^ to the 

 far greater number of the species, and not to any du*ect influence 

 of the climate (p. 191). 



(8) The following laws control the color-patterns of butterflies 

 and moths : (a) Any spot found upon the wing of a butterfly or 

 moth tends to be bilaterally symmetrical, both as I'egards form and 

 color ; and the axis of symmetry is a line passing through the center 

 of the interspace in which the spot is found, parallel to the longi- 

 tudinal nervures (p. 183). (b) Spots tend to appear not in one 

 interspace only, but in homologous places in a row of adjacent 

 interspaces (p. 183). (c) Bands of color are often made by the 

 fusion of a row of adjacent spots, and, converse^, chains of spots 

 are often formed by the breaking up of bands (p. 183) . (d) When 

 in process of disappearance, bands of color usually shrink away at 

 one end (p. 184). (e) The ends of a series of spots are more 



