184— OBSERVATIONS ON CULEX PIPIENS. 
Northern European type of the common house mosquito, which 
seems to have established races slightly differing one from 
another over a world-wide range. Linnzeus’ second species, 
bifurcatus, is now identified with the genus Anopheles, and is 
the type of the malaria-carrying insects which have been 
grouped under this name. 
Both species are known to occur in the United Kingdom, 
and the prevalence of ague in the Fens and some other parts 
of the kingdom at one time has recently been ascribed to the 
agency of Anopheles. The general improvement of drainage 
in the last half century has practically done away with their 
breeding places, or, at least, reduced them to such an extent 
that they cou!d no longer function in this way, and malarial 
ague has disappeared. 
Both species may, however, still be found, and my atten- 
tion was attracted specially during the summer months of 1916 
to the prevalence everywhere I went of the pipiens mosquito. 
Its hibernating habit was recorded in 1900 from Shrewsbury, 
where in the month of January it was observed resting in 
cellars and other sheltered nooks, found on the wing in March, 
observed biting in April, and swarming outdoors from June 
till October. 
It is probably the fertilised female only which survives 
through the winter, and at the first opening of ponds and 
water-holes lays her eggs in places where they may develop 
and successive generations rapidly follow, by which the multi- 
plication of the species is secured. The egg’s are laid in the 
form of a raft, some 80 to 100 egg’s in a boat-shaped mass are 
extruded and float on the surface. The larve break their way 
from the eggs and escape into the water, in which they move 
freely about, diving for food and again coming to the surface 
for air, which is breathed through the air syphon which pro- 
jects almost at right angles from the precaudal segment, on 
the dorsal side. This stage lasts seven days, or under dis- 
advantageous conditions a few days longer. Pupation then 
takes place, and in a few days the adult mosquito emerges, 
and after a short rest to dry the wings, sails off in search of 
blood or amours according to sex, for it is the female alone 
which seeks a meal of blood and so makes herself a pest fo 
