AROMATIC BUTTERFLIES. 1051 



According to Aurivilliiis, l)otli male and female of Ocneis noma of Eu- 

 rope have a musky odor, aud as he can discover no odor in either sex of 

 Mancipiura brassicae, a species in which tlie male possesses large androco- 

 nia. he looks askant at the so-called scent scales described by Fritz Miiller. 

 But if the species of Oeneis named possesses this odor in both sexes, it is 

 probable that it does not arise from the scent scales but from some other 

 source, probably from some abdominal excretory organ, such as Miiller 

 has described in many other butterflies. I have been unable to detect any 

 odor in three other species of Oeneis examined alive by me, and tliey, like 

 Mancipium brassicae, are merely some of many instances in which our 

 senses cannot perceive an odor presumably emitted. Lelievrc, again, 

 found that both sexes of Thais polyxena had on eclosion, when handled, an 

 odor similar to that of its food plant Aristolochia, the odor arising 

 from a fluid which was left upon the hand that had seized the insect. 

 The European Papilio machaon is also said to sometimes exhale a distinct 

 odor of fennel, upon wliicli the larva feeds. All these, however, are plainly 

 means of defence, if they have any purpose, and have no relation to the 

 odors of scent scales. Nor does it appear that any organs for their pro- 

 duction have been noted. Among the moths Reichenau records a musky 

 odor in the male of Sphinx ligustri, which he traces to a bundle of color- 

 less scales thrust out from either side of the first abdominal segment. Miss 

 Soule says that both sexes of Samia cynthia emit a rank odor. 



The statement by Miiller that the fragrant odors emitted by butterflies 

 are in some cases produced by peculiar scales found in the male sex and 

 which he terms scent scales, was received with a great deal of incredulity, 

 and rightly, because the wing of an insect was looked upon, at least after 

 the butterfly had flown a while, as an almost completely dead organ. But 

 the fact that anyone may experiment with our own butterflies and in 

 several cases prove to himself the exact location of an odor, removes in 

 the first instance any possible doubt as to its origin ; and Weisniann, in 

 defending Miiller, has clearly shown that there is a living tissue in the wings 

 of butterflies which would allow of the production of an odor through local 

 active scent glands. 



It seems, therefore, to be clearly proved that veiy nuiny butterflies emit 

 odors either of an agreeable or of a disagreeable nature, and that those which 

 are pleasing to us are in large measure confined to the male sex and are 

 emitted through microscopic canals which course through microscopic 

 scales to microscopic glands at their base within the wing membranes. 

 Now it is quite plain that, since these insects emit odors, they must 

 also be able to perceive them. That this is the case has always been 

 known to be true of moths, since the males of certain species, especially 

 among the Bombycidae, will of an evening enter in great numbers an open 

 room within which a female of the same kind has been disclosed from 



