375 
and in the same condition in the infected mosquitoes throughout the 
winter, I refrained from examining more in the autumn, but endeavoured 
to keep a number alive, which Mr. Bacot brought me. The mosquitoes 
were placed, some in small cardboard boxes, and the rest in stiff paper 
rolls, loosely plugged at both ends with cotton-wool. Both lots were 
covered over with fine sand, to retain dampness. Some of both lots were 
placed in a fairly damp spot in a cool greenhouse, others were kept in 
a room, cold but comparatively dry. Half-a-dozen or so of the mos- 
quitoes were left to their own devices in an ordinary mosquito cage in 
the same room. These last were observed at intervals during the course 
of a month, remaining motionless during this time. At the end of Oc- 
tober one of them was examined and just the same condition of affairs 
was found, the parasites being abundant. All were then left undisturbed 
over the winter, and at the end of March I looked to see how they had 
fared. Three were found still alive in the cage, but unfortunately not 
one of the others, specially cared for, remained alive. They had all been 
destroyed by a blue mould. This was entirely unexpected, both by 
Mr. Bacot and myself. It was certainly neither the effect of tempera- 
ture nor of the degree of humidity, for, as just noted, some were still 
alive in my (relatively) dry room and Mr. Bacot found also some still 
in his (relatively) very damp cellar, although here, too, the mortality 
had been very high. In the case of those I kept, it was probably the 
confining of the air, even to the extent caused by the loose cotton-wool, 
which had sufficed to kill them. 
In one of the three which remained alive in my cage and in about 
40 % of those examined which Mr. Bacot was again able to obtain from 
his cellar in the spring, the parasites were present, and broadly speaking, 
in the same condition as they were in at the beginning of the hibernation, 
both as regards numbers, form and behaviour. One point of difference, 
which is well seen in the permanent preparations, is that the parasites 
now lack the large conspicuous granules which occur in many in the 
autumn preparations. At the most, a few fine granules are observable 
in some individuals (figs. 24, 29). For this reason, it is probable that the 
large granules represent reserve food material which has been used up 
by the parasites during the winter. During the whole of this period, of 
course, the intestine-of the mosquito is empty. 
The most surprising feature about the parasites is that after this 
long quiescent period, they practically all become just as active when the 
alimentary canal is broken up, as those did which were present in the 
females examined in the autumn. I did not at this time see any cysts in 
the living examinations, any more than I did in the autumn. When I 
found that the parasites, although motionless, were merely in the same 
