SCENTS 
493 
I think it well to note whether the result is obtained in the field, or 
in the house, and in the latter case whether the insect was alive or 
dead. My practice is to examine in the house every specimen 
captured, but I fear that too often the examination has been very 
hasty, not to say perfunctory. 
A final warning. Beware of faecal odours due to pinching the 
butterfly. Again, a “ mousy odour ” is in several cases recorded ; 
this is not confined to one sex, and is met with in butterfles belonging 
to various families, but only after death . This I believe to be a 
product of decomposition of either the animal juices or the faeces. 
The odour resembles that of acetamide, and not improbably may be 
due to that substance, or some compound ammonia. 
Mr. F. R. D. Onslow has suggested that butterflies might 
conceivably derive their scents from direct contact with flowers. 
Without denying the possibility of this I can only say, after some¬ 
what extensive experience, that the explanation does not fit the facts. 
It has, however, occurred to me as possible that occasionally the scent 
might be derived from the opposite sex. 
It may be added that I am at one with Fritz Muller and Dr. 
Dixey in dividing the scents of butterflies into two categories: 
(1) Attractive scents; in the very large majority of cases confined 
to the male sex ; and (2) Repulsive or protective scents, usually 
common to both sexes, and often stronger in the female. 
There are indeed a few notable exceptions, but so far as the facts 
are available, it would appear that, speaking generally, the Pierinae , 
Satyrinae, and Lycaenidae yield scents belonging to the first class 
(attractive), whereas the Danainae, Acraeinae and Heliconiinae pro¬ 
duce repulsive scents. The Ithomiinae, Nymphalinae and Papilioninae 
contribute scents of both classes. Of other groups little or nothing 
is known as regards scents. 
It is quite certain that in some butterflies two quite distinct 
scents may be detected in the same individual, one transient, the 
other more persistent: it is not improbable that herein may be found 
the explanation of some apparent exceptions, or discrepancies. 
Dr. Dixey has called attention to the somewhat surprising fact 
that (with a few possible exceptions) the scents that are believed to 
be attractive to the opposite sex are agreeable to the average human 
perception, whereas those that are believed to be repulsive (and 
therefore protective) are for the most part disagreeable, or even 
disgusting. 
