Notes on Brazilian Entomology 1 ). 



Odours emitted by Butterflies and Moths. 



Two years ago I ventured to suggest 2 ) that all those various pencils, tufts or 

 manes of hairs, all those chalky, silky or velvety spots of peculiar scales, as well 

 as the recurved margins or other pouches enclosing pale buff or white down, 

 which distinguish the wings of the male sex in many butterflies, might be odo- 

 riferous organs. This suggestion might then have been justly censured as too 

 rash, being founded on the actual observation of odours in four species only, and 

 I felt, of course, the necessity of testing this view by examining as to their 

 odours all living butterflies I might be able to procure. I will here give the 

 results hitherto obtained, enumerating those species 3 ) in which distinct odours 

 could be perceived, and I hope the facts to be given will fully justify my sug- 

 gestion. 



Odours, as well as colours, may have been acquired by butterflies either for 

 protection or as an attraction beetween the sexes. Protective odours appear to 

 be in most cases equally strong in both sexes, or sometimes stronger in the 

 females; they may exist in the caterpillar as well as in the perfect insect. When 

 capable of voluntary emission, they are emitted" as soon as the animal fears some 

 danger, e. g., when it is seized, and this may in some cases serve to distinguish 

 them from sexual odours. 



Sexual odours may be divided into two classes. 



Firstly, those which give notice to the opposite sex of the existence of, and 

 lead it the way to, the odoriferous animal. Such odours must exist in many 

 female moths wich attract the males from great distances. Among butterflies the 

 males appear to be guided more by the colour than by the odour of their 

 females. 



Secondly, those odours which do not serve as a guide, but as an excitement 

 to the opposite sex. They appear to be by far more frequent in the males, 

 though occurring also in some females. Odours of both classes will of course 



1) Trans. Ent. Soc. Part. III. 1878. p. 211 223. 



2) Jenaische Zeitschrift fur Naturwissenschaft, XI. p. 99. = - Ges. Schriften S. 534. 



3) I am much indebted for the names of the butterflies mentioned in this paper to Prof. A. 

 Gerstaecker and Dr. O. Staudinger. 



