FRAGRANT BUTTERFLIES—CLARK 443 
sudden shifting of position, is also characteristic of the courting of 
Cercyonis alope (fig. 35, pl. 6); but the performance usually takes 
place upon a tree trunk or some broad surface more or less near the 
vertical, and the male commonly moves up so that the two sit side 
by side. 
In the common sulphur (Hurymus philodice) (fig. 7, pl. 1; figs. 
20, 21, pl. 3), the courting of the male always is accompanied by a 
constant fluttering of the wings, with the fore wings drawn well 
forward; but in this butterfly the female usually sits with her wings 
widely spread, the fore wings drawn well back. 
In all these cases it is evident that the male endeavors to envelop 
the female with his perfume, which in the first and last is wholly 
different from that of any flower upon which the insect feeds. Were 
the odor of the males really attractive to the females as has been 
assumed, and as the fragrance of the flowers is, there would surely 
be no need for such persistence as the males exhibit. 
The natural conclusion therefore is that the odors of male butter- 
flies are in reality sex stimulants, like the odors of the males in other 
creatures. Such odors, though all serving the same purpose, may 
or may not be agreeable to our senses, and this is probably the reason 
why in certain butterflies the males seem to us to have a most un- 
pleasant smell. 
Undoubtedly the nauseating odors of the subterminal organs of 
the female fritillaries are protective in their function. The chief 
enemies of these butterflies with us undoubtedly are mice. I have 
noticed that discarded individuals dropped into the meadow grass 
were by the next morning invariably eaten. But these butterflies 
always spend the night as near the ground as possible, crawling 
down the grass stems and often many feet along the ground, hiding 
away in the débris close to the soil, much as in the spring their cater- 
pillars hide themselves away during the daytime. Here they are 
exposed especially to attacks by mice. The females of our fritil- 
laries seem to be much longer lived than do the males, for by the 
end of August in New England all the still fairly numerous indi- 
viduals remaining are females busily engaged in searching for their 
food plants and depositing their eggs. 
Whether the much longer life of the female fritillaries results. 
from superior vitality or from superior protection against mice is 
an interesting question, 
The females of all our fritillaries are larger and more conspicuous 
than the males, and at the same time less shy with a less swift and 
less erratic flight. It may be that when on the wing the males are 
protected by the more conspicuous and more readily caught females 
with their powerful repellent organs. 
