No. 5. — The Development of the Wing Scales and their Pigment in 
Butterflies and Moths.1| By ALFRED GOLDSBOROUGH MAYER. 
Tuts research has been carried out under the direction of Professor 
Edward L. Mark, to whom I am so fortunate as to be indebted for much 
valuable advice and happy suggestion. 
During the summer of 1895 I carried out a series of observations 
upon the development of the colors in the pupal wings of Danais plexip- 
pus (archippus) Fabr. and Callosamia promethea Linn. The results of 
these observations will be published in connection with a paper entitled, 
“On the Color and Color Patterns of Moths and Butterflies,” which it 
is expected will appear during the present year. I may state here briefly 
the main conclusions reached on those subjects. 
It appeared that during early pupal life the wings are as transparent 
as glass, but that from five to ten days before emergence they become 
opaque, and pure white. After this a dull ochre-yellow or drab color 
suffuses the wings, tingeing all parts excepting those that are destined 
to become the white spots of the mature wing, these always remaining 
pure white. 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 dis- 
tinguished by the fact that they first appear upon areas between the 
nervures, never upon the nervures themselves. Indeed, the last places 
to acquire the mature coloration are the outer and costal edges of the 
wings, and the nervures. 
The progress of the color development is illustrated in Plate '7, where 
Figures 53-70 represent the color development in Callosamia promethea, 
and Figures 71-74 the same thing for Danais plexippus. Figure 53 
represents a fore wing of C. promethea in the white stage, and Figure 
54 is a scale taken from the same wing. Upon treating the scales in 
this stage with clove oil or oil of cedar-wood they become practically - 
invisible under the microscope, thus demonstrating that there is no pig- 
1 Contributions from the Zodlogical Laboratory of the Museum of Compara- 
tive Zodlogy at Harvard College, under the direction of E. L. Mark, No. LIX, 
VOL. XX1X. — NO. 5. 1 
