AROMATIC BUTTERFLIES 111 



same position on the Iiincl wings a musk-like odor 

 of varying degrees of strength according to the 

 species. He adds that our own Cloudless Sulphur 

 (Callidryas eubule) emits a faint musk-like odor, 

 but this has been more carefully and indepen- 

 dently determined by Miss Murtfeldt of Missouri 

 as a slight violet odor ; she was unable, however, 

 to locate the spot from which the odor originated. 

 Again, according to Miiller, a " very delicious 

 perfume " is produced on the upper side of the 

 wing of the male of the species of Melete already 

 referred to, a perfume which is rather faint, but 

 which may be rendered distinct by keeping the 

 animal alive with the wings closed, when the odor 

 may be perceived on opening them. Another 

 instance in which two closely allied species may 

 vary in regard to their odor is found in our 

 species of Pieris, the males of the Cabbage butter- 

 fly (Pieris rapae) being only faintly odorous, 

 while those of the Gray-veined White (P. olera- 

 cea) have a more distinct but still faint odor of 

 syringa blossoms ; so, too, the Green- veined White 

 (P. napi) of Europe is said by different writers, 

 de Selys Longchamps, Perkins, Weismann, to 

 have the odor of thyme, verbena, orange, or bal- 

 sam. The only one of our Papilioninae in which 



