8 
Nuttall found that A. quadrimaculatus, which hibernated in the winter in 
Cambridge, was observed to disappear in May, “ no doubt to oviposit and then 
to die.” 
Grassi (in Nuttall and Shipley, 1902) says that he has never found the males 
of A. maculipenni8 hibernating but only the females, all of these being fecun¬ 
dated. They begin to disappear in February, in Italy, and vanish to a greater 
extent in March when at times none are to be found. These insects have, pre¬ 
sumably, flown out and died after depositing their eggs. 
Austen (1901) cites his observations in England as follows: “In colder 
climates, on the other hand, impregnated females survive the winter in some 
suitable retreat in a state of hibernation, during which they take no food, de¬ 
positing their eggs at the commencement of warmer weather.” 
Annett and Dutton (1901) in the course of their observations on the hiberna¬ 
tion of English mosquitoes never found any of the mosquitoes in stables and 
cattle sheds, as these places were comparatively dry and warmed by the ani¬ 
mals at night. Not a single male A. maculipennis was seen during several 
months in the winter. This fact they interpret as indicating that it is the 
female alone that hibernates. 
Stephens (1908), writing on the length of Anopheles life, states: “It was 
originally supposed that mosquitoes, when they had laid their eggs, died. The 
observations are, however, probably true of these mosquitoes which have 
hibernated during the winter (in a fecundated state). On the return of 
spring they sally forth and lay their eggs and die.” 
Stephens assumed that the hibernating Anopheles are all females and these 
are always fertilized; that the females, if roused from their sluggishness by 
bringing them into a warm room, will feed, and after a time lay eggs; if, 
however, the temperature be kept low, they do not arouse themselves and 
do not feed. 
Giles (1902), referring to the seasonal inactivity of Anopheles, states that 
this habit is spoken of as hibernation, and in Europe, where the males ap¬ 
parently all die before winter has fairly set in, only impregnated females sur¬ 
vive the winter, “ and it is through their agency alone that the continuity of 
the species is maintained.” 
Howard, Dyar, and Knab (1912), are quoted as follows: “With the ma¬ 
jority of the species of mosquitoes the unfavorable season is passed in the egg 
state. Certain genera, however, pass the winter in the adult state. In such 
cases it is only the female that survives, having been previously fertilized, to 
deposit her eggs at the beginning of another season. It is certain that, at least 
in the genera Cnlex and Anopheles, no males survive the winter. The hibernat¬ 
ing females seek shelter with the approach of cold weather, and at this time 
they show no inclination to feed. Those species more or less associated with 
man take advantage of the shelter of cellars, stables, sheds, and other out¬ 
buildings, the darkest ones apparently being the most favored. They have 
also been found hibernating in caves. Other species retire to hollows in 
trees, crevices in the bark, or other protected situations. There they remain 
quiescent until the return of the warm weather, closely hugging the surface 
upon which they rest.” 
Rosenau (1913) remarks: “The way in which mosquitoes manage to pass 
through the rigors of the winter probably varies with the different species. 
Some, like the malarial Anopheles, hide in sheltered cellars or dark nooks, or 
hibernate in other out-of-the-way places. Other species survive through the 
power of the larva or egg to resist cold, for the larvae or eggs of some species 
will hatch even after they have been frozen.” 
