284 
Psyche 
[December 
None of the localities summarized in tables 2 and 3 were far 
enough inland to show any marked difference ifi winter mortality 
that might be associated with any climatic factor. In fact all 
these localities are in a very small area, somewhat larger than the 
area covered by the examinations of the previous year but confined 
to the heavily infested regions for the reason previously stated. 
The experimental work, on the other hand, shows very clear 
differences in winter mortality. An experiment was placed in 
the late fall of 1922 in each of twenty localities representing all 
sections infested by this insect at that time. These experiments 
were placed in the field in November, 1922, after activity of the 
insect had ceased and were recovered in ilpril, 1923, before 
spring activity began. Migration of larvae from the corn stalks 
was for this reason limited to a few individuals. Each experiment 
consisted of ten stakes to each of which were fastened six in- 
fested stalks. The findings in the spring of 1923 may be best 
shown in the following table. 
TABLE No. 4. 
Winter Mortality Found in the Experimental Material in the 
Spring of 1923. 
Locality 
Date 
placed in 
field 
Date 
re- 
covered 
Total 
num- 
ber of 
larvae 
re-cov- 
ered 
Num- 
ber of 
larvae 
dead 
Per 
cent of 
winter 
mor- 
tality 
Average 
per cent 
of winter 
mortal- 
ity in 
group 
Bristol, N. H. 
11-8-22 
4-26,-23 
1397 
307 
41.9 
Farmington, N. H. 
11-7-22 
4-25-23 
1341 
559 
41.7 
35.5 
Wells, Me. 
11-7-22 
4-25-23 
1132 
507 
44.8 
Tyngsboro, Mass. 
11-8-22 
4-14-23 
990 
161 
16.3 
22.6 
Concord, Mass. 
11-4-22 
4-10-23 
854 
256 
29.8 
Methuen, Mass. 
11-2-22 
4-14-23 
1014 
52 
5.1 
Worcester, Mass. 
10-26-22 
4-11-23 
1222 
34 
2.8 
Walpole, Mass. 
11-6-22 
4-11-23 
661 
32 
4.8 
3.9 
Quincy, Mass. 
11-4-22 
4-11-23 
944 
31 
3.3 
Manomet, Mass. 
10-30-22 
4-6-23 
1081 
14 
1.3 
Wareham, Mass. 
11-1-22 
4-8-23 
1066 
10 
.9 
Falmouth, Mass. 
10-31-22 
4-7-23 
1135 
13 
1.1 
.88 
Harwich, Mass. 
11-1-22 
4-6-23 
909 
9 
1. 
Wellfleet, Mass. 
10-31-22 
4-7-23 
1106 
1 
.09 
