a handbook of the mosquitoes of north america - Systematic Catalog ...

CHAPTER II
THE BIOLOGY OF MOSQUITOES
GENERAL CONSIDERATIONS, EGG-LAYING HABITS, LARVAL
HABITS AND HABITATS, HABITS OF THE
ADULTS, HIBERNATION
During their life-cycle, mosquitoes undergo a complete meta-
morphosis, i.e., from the egg hatches a larva, this transforms
into a pupa from which the winged adult later emerges (Figs.
13, 14, 10, and 12). The larval and pupal stages of all
species are aquatic-they can be found only in water and each
species seems to select a special type or types of aquatic habi-
tats.
The life-cycle of the common house or rain-barrel mosquito,
Culex @pieas (typical for the genus Ctilex), may serve to il-
lustrate mosquito biology. The fertilized females (Fig. 12)
hibernate in various shelters as attics, cellars, cow sheds, sta-
bles and out-buildings of all kinds where protection and semi-
darkness are found. The males all die with the approach of
winter. Enormous numbers of females may hibernate in very
small shelters. I have estimated from careful counts of definite
areas that over 100,000 hibernated in a small c1a.rk cellar not
over four feet by six feet with a height of only seven feet.
Scarcely a pinpoint could be found on which a mosquito did
not cling to ceiling, walls, hanging ropes and a pump which oc-
cupied the centre of the small room. During the cold weather,
the hibernating individuals show little activity though occa-
sionally they invade the warmer rooms. in search of blood.
With the approach of spring, activity is resumed and the fe-
males seek suitable places for oviposition. Depending on the
locality, egg-laying begins in May or June. Each female de-
posits from 100 to 400 or more eggs in a boat shaped mass
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