AMERICAN NATURALIST. 
Vol. VII.—- MARCH, 1873.— No. 3. 
* 
EIEL OD 
CONTROLLING SEX IN. BUTTERFLIES. 
BY MRS. MARY TREAT. 
Tuar sex can be controlled in butterflies, I think I have demon- 
strated by careful experiment the past season. Accident first 
prompted the experiment. Two years ago this past summer, I 
was feeding a few.larvæ of Papilio Asterias for the cabinet, when 
one of my specimens wandered from its food, and rested upon a 
book to undergo its transformations. Not feeling inclined to give 
up the book to this purpose, I placed the larva on a fresh stem of 
caraway ; upon removing it from the book, I found its feet were 
entangled in silk, and that it was in position for a chrysalis, but 
not yet fastened ; so I was surprised to see it commence eating. 
It continued eating some days longer, before changing to a chrys- 
alis. I then tried others in the same way, and also took off quite 
a number of larvae, shutting them away from food. Some of the 
larvee that I deprived of food in this first experiment died, but all 
that completed their transformations were males; while those 
that I induced to go on feeding by tempting them with the best 
and freshest food proved to be females. 
This season (1872) I commenced with the larve the 17th of 
June, and continued feeding broods of different ages through the 
month of July. Early in July I had about two hundred larvee 
feeling at the same time. The room in which I conducted my 
experiment faced east and south, and toward noon of each of those 
excessively hot days in the early part of July, it was several 
degrees warmer than in the outside air. The food-plant on which 
I fed the various broods was placed in jars of water, which were 
ra eines = 
Entered, according to Act of Congress, in the year 1873, by the PEABODY ACADEMY OFP 
CIENCE, in the Office of the Librarian of Congress at Washington. : 
AMER. NATURALIST, VOL. VII. 9 (129) 
