20 
experiment where 3 mosquitoes, which had not laid eggs at a tem¬ 
perature of 3°-6.5° C. for one week, were transferred accidentally 
to another compartment of the refrigerator where the temperature 
registered 9°-12° C. Six hours elapsed before the misplaced cage 
was discovered, when it was noticed that about TO eggs had been 
deposited. No more eggs were laid when the mosquitoes were re¬ 
turned to the low temperature compartment and the eggs subjected 
to room temperature did not hatch. This phenomenon might be ap¬ 
plied to natural conditions of hibernation in which, during the 
normal low temperature of winter, a rise of 2.5°-5.5° C. would 
afford an opportunity for Anopheles to oviposit. 
The temperatures recorded during the hibernation studies are 
tabulated as follows: 
Table No. II .— Temperatures and rainfall during January-May, 1015. 
(Recorded at office of Mississippi Delta Planting Co.) 
Week. 
January. 
February. 
March. 
Mini¬ 
mum. 
Maxi¬ 
mum. 
Mean. 
Mini¬ 
mum. 
Maxi¬ 
mum. 
Mean. 
Mini¬ 
mum. 
Maxi¬ 
mum. 
Mean. 
-2.5 
-2.0 
-1.5 
—5.5 
-1.5 
17.0 
14.0 
19.0 
17.0 
18.0 
6.5 
5.5 
6.5 
1.5 
4.0 
-1.5 
0.0 
1.5 
3.0 
15.0 
21.0 
16.0 
20.0 
7.0 
10.5 
10.5 
7.0 
0.5 
2.0 
—0.5 
-3.0 
1.0 
17.5 
14.0 
IS. 5 
19.5 
20.5 
7.0 
6.5 
8.5 
8.5 
10.5 
3.64 
0.67 
5.56 
1.83 
First. 
Second. 
Third. 
Fourth. 
Fifth. 
Monthly rainfall 
Snow. 
Week. 
April. 
May. 
Mini¬ 
mum. 
Maxi¬ 
mum. 
Mean. 
Mini¬ 
mum. 
Maxi¬ 
mum. 
Mean. 
First. 
2.0 
25.5 
12.0 
15.5 
32.0 
23.5 
Second. 
1 10.0 
28.0 
20.0 
12.0 
31.0 
19.5 
Third. 
12.0 
31.0 
20.5 
15.5 
34.0 
25.0 
Fourth. 
15.0 
32.0 
23.5 
18.5 
33.5 
26.0 
Fifth. 
19.5 
34.0 
26.0 
12.5 
29.0 
21.0 
Monthly rainfall. 
0.89 
5.57 
Snow. 
Collateral studies conducted January 3-9, 1916, at Talladega Springs, Ala., 
a fairly well isolated country town, furnished us with the following informa¬ 
tion. At this place the investigation was not made primarily for the study of 
malaria hibernation, but incidental to securing specimens of anophelines for 
biting experiments. One week was spent at this place, the nature of which 
differs in one important particular from that of the locality investigated in 
Mississippi, the presence of commodious, substantially built animal sheds. 
These places were found to harbor more than 50 per cent of the total number 
of Anopheles collected. This condition has also been observed in other localities 
in the South by service officers making malaria surveys during the winter 
months. Possibly the predilection of anophelines for the blood of cattle and 
horses may exert an influence on the loss of malarial infectivity of these insects 
