July, '09] ENTOMOLOGICAL NEWS. 293 



A Case of Replacement of Color in Papilio ajax Linn. 



WILLIAM W. NEWCOMB, M. D., Detroit, Mich. 



An interesting example of replacement of color occurred 

 in the course of an experiment to determine the effect, if any, 

 of different colors upon the growing larvae and the chrysalids 

 of Papilio ajax. One of the latter, instead of producing the 

 usual summer form of the species (marcellus) with the vivid 

 crimson markings, disclosed an imago in which these were all 

 replaced by yellow. The difference is very striking especially 

 when a specimen of the normal form and the one under con- 

 sideration are directly compared, the crimson stripe and the 

 two spots of the crimson bar of the under surface of the hind 

 wing of the one contrasting strongly with the yellow of the 

 corresponding parts of the other; the antennal spot on the 

 upper surface is only less conspicuous because of the single 

 spot. This unique specimen is a male which emerged Septem- 

 ber 3, 1906. 



It may be worth while to note the conditions under which 

 the replacement occurred. I was engaged in rearing a con- 

 siderable number of larvae of ajax from eggs of imago, in 

 each experiment subjected to the influence of the same color 

 throughout their lives. Breeding boxes were used in which 

 the inside in each case was entirely of the one color including 

 the material to close the openings for the admittance of light 

 and air. The specimen showing the replacement came from 

 the box in which the lining color was maroon and was the 

 only butterfly that emerged from this box in the summer or 

 fall, all the others some twenty-two in number passing the 

 winter in the chrysalis and hatching in the spring without any 

 change from the normal in regard to the crimson color. 



Why should a single specimen have shown this variation of 

 color, notwithstanding the fact that all the larvae and chrysal- 

 ids were kept under the very same conditions? Unfortu- 

 nately only one butterfly was disclosed in the fall of the year; 

 the length of time in the chrysalis then, may perhaps be con- 

 sidered as a different factor, but it is, however, the only one. 

 Had a second specimen showing the replacement emerged in 



