178 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



under side of the mature wings of Vanessa io is mainly uniform 

 black, and in this case also this color develops from the white at a 

 very rapid rate, near the end of the pupal stage. This development 

 of the black directly upon the white areas is quite remarkable in 

 Vanessa io, and very different from that of both Vanessa m-ticae 

 and Pyi-ameis cardui, where the black spots develop upon a field 

 already tinged with red. Urech points out the fact, that some of 

 the white spots seen in the mature wings of the Vanessas represent 

 the " primitive white " of the pupal wings. 



Finally, the latest paper upon the subject of the development 

 of color in the pupa is that of Haase ('93), who has examined 

 the pupae of a number of Papilios (e. g.^ philenor, machaon, 

 asterias, turnus, and podalirius), and finds that during earh' pupal 

 life the wings are as transparent as glass ; after a time, however, 

 they change to an impure white, which soon becomes yellowish, and 

 then the various colors which are destined to adora the mature 

 wings begin to appear. 



If we are to learn much of fundamental import concerning the 

 phylogeny of color in Lepidoptera, the researches should be carried 

 out upon the lower moths, and not upon such highly specialized 

 forms of Rhopalocera as the Vanessae. 



In my paper on Wing scales, etc. (Mayer, '96, p. 232), I have 

 come to the conclusion that dull ochei'-yellow and drabs are, 

 phylogenetically speaking, the oldest pigmental colors in the Lepi- 

 doptera. 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. 



I have made a study of the development of the colors and pattern 

 in the wings of Callosaniia promethea Linn, and of Danais plexip- 

 pus Fab. 



(2) Development of Color in the Pupal Wings of Callosamia 

 promethea. The cocoons of Callosamia promethea are very abundant 

 during the winter months, when they may be found hanging to the 

 stems of the food plants of the larvae. The pupal Avings remain 

 perfectly transparent all through the Avinter, until about ten days 

 before the time when the moth is destined to issue ; they then become 

 opaque white. An examination of the wings at this period shows 

 that the scales are perfectly formed (Fig. 25, Plate 3), except for the 



