19 
The following table summarizes the results of these tests. * The 
mosquitoes used were Anopheles quadHmaculatus placed in various 
compartments of two refrigerators, the temperature being carefully 
registered three times a day. The mosquitoes were captured speci¬ 
mens kept in lantern chimneys, the upper ends of which were closed 
with coarse bobinet and the lower ends immersed in water contained 
in flat dishes. The higher temperatures were secured from an elec¬ 
trically controlled, low-temperature incubator set at 19-21° C. and 
from living room and outdoor exposures at temperatures of 16-35° C. 
Table No. I .—Summarizing the results of egg production and hatching at 
various temperatures. 
Temperature C. 
Number 
of mos¬ 
quitoes 
used. 
Results. 
Duration of experi¬ 
ment. 
4.5- 5.5.. 
15 
Negative. 
Sept.3-Oct. 15. 
4. rt— fi. 5__ 
62 
Negative. 
Aug. 20-Sept. 6. 
7. 7-11.5 
12 
Negative. 
Aug. 20-Sept. 1. 
9.5-12.5. 
12 
Negative. 
Aug. 20-Sept. 6. 
13.5-16.7_ 
12 
310 eggs. No larvse. 
Aug. 20-Sept. 1. 
19.0-21.0. 
12 
425 eggs laid in 7 davs. Fertile. 
Aug. 20-Aug. 27. 
22.5-32.0. 
12 
2S0 eggs laid in 4 da vs. Fertile. 
Aug. 20-Aug. 24. 
21.0-33.5 . 
12 
700 eggs laid in 4 days. Hatching begun within 
Sept. 3-Sept. 8. 
30 hours. 
16.0-35.0. 
14 
800 eggs laid in 2 days. Hatching begun in 24 
Sept. 3-Sept. 7. 
hours. 
The temperature tests were conducted during the period from 
August 20 to October 15, 1915. Xo cognizance is taken of the fate 
of the mosquitoes after egg deposition was completed. Interpreta¬ 
tion of results in some instances must allow for the unprepared¬ 
ness of females to lay eggs, although they were kept a reason¬ 
able length of time to encourage egg development. Therefore no 
significance is placed on the percentage of eggs laid at the different 
temperatures. As a check to the negative results obtained at tem¬ 
peratures included between 5.5°-12.5° C., the mosquitoes surviving 
at the termination of the tests were subjected to temperatures at 
which successful egg laying had been previously observed. These 
favorable temperatures were obtained in the room or outdoors vary¬ 
ing from 16° to 35° C. Although eggs were laid freely their 
germinating powers were markedly enfeebled, since only 35 per cent 
to 75 per cent of the various lots produced larvae. 
It will be noticed that the temperatures 13.5°-16.7° C. produced 
310 eggs, but no larvae, at the end of 12 days. The fertility of 
these eggs was tested in the incubator at a temperature of 19°-21° 
C., when 100 per cent of them hatched within 48 hours. 
It must be borne in mind that the conditions of these tests are 
strictly artificial, especially in subjecting mosquitoes to ice-cooled 
air when directly removed from much higher outdoor temperature. 
Probably a fairer test, simulating natural conditions, would obtain 
in a gradual fall or rise in temperature. This was indicated in one 
