136 
Dr. Pallas’s Observations 
XXV. Observations on the Habits of the Purple Emperor 
(Apatura Iris). By the late P. S. Pallas, M. Z). # 
[Read December 5th, 1836.] 
I found the caterpillar of the purple emperor ( Papilio Iris, 
Linnaeus,) in the year 1755. It was climbing up the trunk 
of the willow-tree, from whence it had been disturbed by a storm 
of wind ; full grown as it was, it began, the second day I found 
it, to prepare for its change, refusing to take any more nourish- 
ment. I was very agreeably surprised some time afterwards to 
see the purple emperor come out of the chrysalis ; and the more 
so, because the changes of this fly had not been recorded by any 
author I knew, which may be chiefly owing to its scarceness in 
most places. 
I had taken a drawing of the caterpillar and its chrysalis, but 
I was desirous to see all the changes and to observe the manner 
of it from its very birth to its state of perfection, as I had done 
with many others before, having planted, for that purpose, the 
most common trees of my country in a little garden in pots for 
the better observing them. 
I could not doubt of this caterpillar’s feeding upon the leaves 
of the willow, upon which stem I had found it, since the fly is no 
where to be found in plenty but about willow plantations, and but 
seldom about oak-trees. Therefore, to obtain a sufficient number 
of the eggs of this butterfly, 1 caught, the following year, as many 
as I could get, in the willow plantations which cover the high- 
ways about Berlin, where, about the middle of June, this fly is 
annually seen in great numbers, gathering in flocks about the 
gums that issue out of the stems of willow-trees, which it loves 
extremely fas also several other flies and the rose-beetles do). 
I learned soon to distinguish the sexes of them, which you may 
do at the first sight, and even whilst they are fluttering in the air, 
for the female never shows that bright purplish gloss which dis- 
guishes the wings of the male at a certain position. I do not find 
this remark in any of the authors that have mentioned this fly, 
not even the ingenious Rosel. Mr. Ray describes only the fe- 
male. Rosel and Wilkes have figured only the male. 
There are two varieties of both sexes, one with white, the other 
* These observations were communicated to Mr. Baker, F. R. S., and by him 
presented to the Aurelian Society. They remained however unpublished, and 
came into my hands with other entomological manuscripts of the late Mr. Drury* 
— J.O. W. 
