406 Transactions. 
pools remains about the same. Even towards the end of summer, thoug 
a pool may be crowded with larvae, there do not seem to be more adults 
than one sees in November. 16 is probable that the normal life of the adult 
is short; nevertheless, I have kept both male and female mosquitoes alive 
in the laboratory for over three weeks. 
Another feature that strikes one as singular is the apparently capricious 
preference given to certain pools. These favourite pools are always found 
e occupied, while others, apparently equally suitable, are either not 
occupied at all, or are occupied in some years and not in others 
The following extract from my notes does not properly come within 
the scope of this paper, but it seems to me to be of sufficient interest to 
warrant publication :— 
. 9nd October, 1921: When watching the mating-tank, observed at 
p-m., an imago standing completely submerged on the side of the 
resting-stone, head downwards. I endeavoured to take the insect by 
means of a pipette; but it immediately walked down the rock till it was 
4 іп, below the surface, then walking along an almost horizontal surface, 
back downwards, to a smaller stone that rested on the floor of the tank. 
It clung so tightly that, even at this depth, it resisted the suction of the 
