MAYER : COLOR AND COLOR-PATTERNS. 179 



lack of pigment, which is developed later. If one treats the scales at 

 this stage with oil of cedar- wood or clove oil, they become practically- 

 invisible under the microscope, thus demonstrating that there is 

 no pigment within them. Fig. 26, Plate 3, gives the appearance 

 presented by a scale taken from the light drab-colored margin of 

 the mature wing. This is about the lightest area upon the wing, 

 except the white spots ; but it will be seen that this scale is much 

 darker in appearance than the unpigmented one shown in Fig. 25. 

 The white or unpigmented condition of the wing lasts for about 

 four days. The wings then become uniformly tinged with an 

 impure yellow or light drab, and very soon after this the colors 

 begin to make their appearance. They first appear upon the lower 

 surface of the wings. Fig. 28, Plate 3, represents the under 

 surface of the fore Aving of a female in a very earh' stage of color 

 development ; in fact the upj^er surface shows, as yet, no trace of 

 the colors. It will be seen that a few dark red streaks have 

 appeared near the central portion of the wing, and it is worthy of 

 note that these occupy the hiterspaces between the nervures. The 

 ocellus near the apex of the wing appears faintly outlined upon its 

 background of impure yellow. 



Fig. 27, Plate 3, represents the under side of a hind wing of 

 a male in about the same stage as Fig. 28. Here, again, the red color 

 occupies the interspaces, and indeed it is only later that the nervures 

 become clouded over by it. 



Figs. 29 and 30, Plate 3, represent, respectively, the under and 

 upper sides of the fore wing of a male about five hours after the 

 first appearance of the colors. Upon the upper side (Fig. 30) we 

 see two gray streaks near the base of the wing and a light cinnamon- 

 brown color extending from the lower edge toward the middle of 

 the wing. The ocellus near the apex is now quite apparent, but 

 still faint in color. On the under surface (Fig. 29) the red markings 

 have developed to a much greater extent than in Fig. 28. The 

 outermost of the two white spots which occupy the center of this red 

 area becomes the white central spot of the mature wing ; the inner- 

 most one is soon obliterated owing to its becoming clouded over 

 with red. 



Figs. 37 and 36 represent respectively the upper surface of 

 the fore wing and the lower surface of the hind wing of a female, 

 slightly more advanced than in Fig. 30. Fig. 31 represents a male 

 and Fig. 38 a female about twelve hours after the first appearance 



