I've found this:
Some kinds of mosquitoes overwinter as adult females that mate in the autumn, enter hibernation in animal burrows, hollow logs or basements and pass the winter in a state of torpor.
Females, in spring, leave hibernation, blood feed and lay the eggs that produce the next generation of adults.
A few mosquitoes overwinter in the larval stage, often buried in the mud of freshwater swamps. As it gets warmer in spring, these mosquitoes start feeding, complete their immature growth and eventually emerge as adults.
To paraphrase Newton-
"All that I know (about insects) is only by standing on the shoulders of gnats"