THE HIBERNATION OF ENGLISH MOSQUITOES 
95 
which we carried on a number of experiments or which we dissected had been 
fertilized (proved by the presence of spermatozoa in the spermatheca, or by the 
hatching out of larvae from deposited eggs). 
A number of experiments relating to the bionomics of the English Anopheles 
maculipennis are at present being undertaken, and we hope to be able to communicate 
the detailed results at a later date. Some interesting facts may, however, be recorded. 
If these mosquitoes be kept in a dry cage they die in a tew days — whereas, as stated 
above, they can be kept probably tor months in a damp cage in the cold, during 
which time they preserve, what we propose to call, the ' hibernating ' attitude. On 
introducing them into a warm room they quickly become active, and both Anopheles 
and some species of Culex eagerly feed on blood on inserting the hand into the cage, 
darkened by covering with a cloth. They then feed eagerly every day for four or 
five davs, but subsequently only occasionally. Eggs were laid on the fifth, sixth, 
seventh, and eighth days, which hatched out in twenty-four or forty-eight hours. It 
was noted that many of the Anopheles died after depositing a batch of eggs. 
We have further observed that having once fed on blood, it is necessary to 
continue the feedings at least every other day, otherwise the ovaries cease to develop 
and the insects die, though water is supplied. This confirms our experiments 
made in West Africa,* where by regular feeding we were able to keep Anopheles 
costalis and funestus alive for a considerable period ; while in the present case of 
A. maculipennis which had been hibernating, most of them died soon after laying 
eggs. 
On the 1 9th April* of this year, during a period of about two weeks of fine warm 
weather, we made another visit to the farms at which we had on previous occasions 
never failed to collect Anopheles. At one farm, three or four Anopheles maculipennis 
were seen, but being so verv active only two were caught. At another some fifty 
were seen, but only ten caught, and these with great difficulty. The mosquitoes 
were exceedingly active, flying immediately the light of the candle fell upon them, 
and directly the bottle was placed near them. This activity strikingly contrasted 
with their slow, lazy movements of the previous week during colder weather. Many 
hundreds of Culex of different species were seen, their increased activity was also 
noticeable. 
On the 23rd of the same month* another visit was made to these farms, but 
no specimen of Anopheles was seen in the sites where previously so many had been 
caotured. At the same time other farms up to now not visited were examined 
without success. At one farm, however, we were allowed to search the whole house, 
and here found five specimens of Anopheles maculipennis, gorged with blood and 
showing developing ovaries, in the attics in which several Irish farm labourers slept, 
Report of the Liverpool Malaria Expedition to the Nigeria, 1901, p. 37-45 
