— 440 — 
number, all younger than the others, and pupating in 27 to 50 days, 
11 died and 23 went over to the winter. 
The B larve, 67 in number, were treated in the same way as A, 
except that their pupa were left at the low temperature for 41 to 
52 days, when some appeared to be on the point of emerging, and 
they were then all removed to the room temperature, where 7 of 
them emerged in from one to 7 days more, all being of /evana 
aspect or neary so; of these 7, 6 were from the first taking of 20, 
consisting of those larva judged to be within 3 or 4 days of 
being full-fed, and one from the second taking of 20, consisting 
of larva judged to be 6 or 7 days of being full-fed. The rest of the 
first and second takings, and all the third taking, numbering 27, 
died or went over to the winter. Of the whole taking of 67, 
26 died and 36 went over to the winter (1). 
Some of the younger larva were transferred for the last week 
or two of their lives to the warm room temperature, pupating 
there in from 3 to 9 days, but none were thus reconverted to the 
summer phase. It may be taken therefore that all the June sum- 
mer phase larva which were more than 6 or 7 days short of being 
full-fed, were converted by a temperature of 50° F. (10° C.) to the 
full winter phase. 
On June 13th, 1910, several hundred larva of A. levana 
were received from North Germany, the most advanced, being 
apparently in their 5th skins, pupating at the room temperature 
from day to day in from one to 10 days, and such of these as were 
left as pupa at that temperature emerged there in about a fortnight 
after pupation (2). A number of those which appeared to be in 

(1) This experiment indicates that, when the larve had not been subjected to 
a low spring temperature until in an advanced period of larval life, the prolong- 
ation of the low temperature into the pupal period caused a Jarger proportion 
to assume the full winter phase, i. e. including the life-habit, than the exposure 
to the low temperature during the larval stage only had done, so that under 
these special circumstances the life-habit in this species may be affected in the 
pupal stage. 
(2) September 25th. Some of these pupæ were on pupation placed at a spring 
temperature of about 55° F. (say 13°C.) for about 6 weeks and then at the room 
temperature; none had emerged when my paper was read on August 4th, 
but having since been transferred to the room temperature, all except a few 
that died emerged in from 1 to 2 weeks time, showing that they remain of 
the summer phase as regards life-habit. In aspect most are foríma, but a few 
are /evana and one frorsa. 
