A. Bacot 
281 
So much by way of preface seems needful in explanation of the 
following detached notes. 
On my return from Freetown in August, 1915, I brought home a 
batch of ova of Stegomyia fasciata, and from these eggs reared adult 
mosquitoes. During November, 1915, a large supply of eggs was 
obtained with the object of ascertaining the extreme period of viability 
of eggs stored out of water but in a humid atmosphere. 
The eggs, laid on filter paper, were placed in a waxed card jar with 
a waxed paper cover and kept in an unused ice chest in a cool cellar. 
This cellar has a bricked but uncemented floor and shows a very even 
range of conditions; the temperature seldom showing more than one 
or two degrees’ variation between night and day, while the percentage 
of humidity is always high. Although circumstances did not permit 
of constant readings during 1915 and 1916, a fairly complete daily 
record exists for the period between November, 1910, and February, 
1912. Monthly averages based on this, together with a chart showing 
curves of maximum and minimum temperatures and the humidity are 
published in the Plague Supplement III of the Journal of Hygiene, 
14th January, 1914, pp. 456 and 461. From this it will be seen that 
the fluctuations of temperature within a period of 16 months lie between 
6-6° C. (44° F.) to 17-8° C. (64° F.) while the record of humidity is even 
more stable, the monthly averages only varying between 91 and 95 %. 
Some thousands of eggs were stored and the numbers used in the 
experiments were correspondingly large. Time did not permit of 
detailed counting, but the round figures given may be taken as approxi¬ 
mately correct, being the outcome of estimates, backed by considerable 
experience of actual counts. 
The immersion tests of the eggs were commenced 7 months after 
laying. 
Tested after 
7 months. 
9 
12 
Result 
Eggs hatched readily during July, 1916, probably not more than 10-20 % 
of the larvae failing to emerge. 
Eggs hatched readily on 31 August, 1916. 
On 2 October, 1916, a very noticeable rise in the percentage of failures to 
hatch was observed. Some of the larvae, however, quitted their eggs 
within two hours of immersion. 
On 4 November, 1916, only a few of the eggs immersed yielded larvae; 
probably not more than 5 %, yet some of these quitted the shells within 
an hour of immersion. Four adults were reared within 10 days and 
8 more within 12 days. 
On 4 December, 1916, 5 larvae emerged from about 600 eggs, but none 
earlier than 5 or 6 hours after immersion. All the larvae were full- 
