A Monograph of Culicidae. 
GG 
HOW MOSQUITOES PASS THE WINTER. 
In tropical climates mosquitoes breed all the year round, with 
periods of rest, however, in the dry or hot season; but in 
temperate climates they breed mainly during the spring and 
summer months. In Arctic regions they probably behave much as 
in temperate climates, but are active for shorter duration. There 
is some variation, however, according to species in every land. 
In North Europe two of the three Anopheles pass the winter 
months in the adult condition in a dormant or hibernating state. 
About the end of October but few Anopheles can be seen. From 
the beginning of October males will be noticed with the females ; 
nearly all the A. maculipennis I have noticed late in the autumn 
have been gravid females. These seek some shelter as soon 
as the weather becomes cold, and lie up during the winter 
months in a dormant condition, appearing early in spring to 
deposit their eggs. Their winter quarters seem to be in crevices 
in outhouses, barns, and cellars. In very warm winters I have 
found this species at all times in the winter months in houses 
and sheds, and in some cases these females seem to deposit their 
eggs, so that we may get the larval state during the cold part of 
the year. 
In tropical climates there is no doubt that a semi-hibernating 
state usually takes place during the dry season just as in 
Europe during the winter, both excessive drought and cold in¬ 
fluencing them alike. “ In the North-West Provinces of India 
and Punjab,” says Colonel Giles, “ although the winter air 
temperature does not fall as low as in Europe, the radiation at 
night is so powerful as to occasionally freeze the small collections 
of water most favoured by mosquitoes ; in any case, to render 
them too cold for the survival of the larvae. In the hot weather, 
on the other hand, all small collections of water are so rapidly 
dried up that it is impossible for the females to find suitable 
places to deposit their eggs, and the power of resting in a 
quiescent condition is as necessary to the persistence of the 
species as it is during the winter of Lapland.” 
This does not appear to be always the case, as the appended 
more recent communication shows. This interesting note 
regarding the hibernation of Anopheles in the North-West 
Provinces of India is also from Lt.-Col. Giles. 
