65 
Pairing of Gnats. 
Heavy downpours would tend to wash or scour out small 
puddles and vessels, and so probably destroy large numbers of 
larvae and pupae ; hence, after continuous rain, as Mr. Tait 
says, they may become much scarcer. 
Possibly very prolonged frost may kill the larvae, but it does 
not affect them to the extent it is supposed to. This year (1901) 
a barrel in which Anopheles larvae were living was frozen over 
for a week in January, the ice being two inches thick. I natur¬ 
ally expected to find all the larvae dead, but not one seemed to 
be affected, and they are still (February) all growing slowly. 
This species {A. hifurcaius) lives over the winter, and hence 
cannot be affected by frost. Whether other species act in a 
similar way I do not know. When the temperature was 30° F. 
I found female A. maculipennis still active in an outhouse. 
PAIRING OF GNATS, 
It is strange that so few observations have been made upon 
this subject. No doubt there are considerable differences in the 
various groups. Speaking generally, gnats pair towards evening. 
I have watched the process in Calex pipiens , but in no other 
species. 
The males assemble in large numbers, flying about in clouds, 
scattered over a small area. In C. pipiens the male clusters that 
I have noticed were composed of from fifty to a couple of 
hundred individuals in small cloud-like groups, very similar to 
Tanypus and other Cliironomidae. 
On still evenings the females fly to the males* and are at 
once seized by them, the two then floating away in copula from 
the rest. In one instance a small female Anopheles maculipennis 
flew into a cloud of male C. pipiens , and she was immediately 
seized and carried off. 
The males of the Culicidae in general seem to avoid houses, 
<fec., where the females go. I have never seen a male G. pipiens 
or of any other European species indoors. But in Anopheles the 
males, in the case of A. maculipennis , often come into houses, 
privies, and sheds, and breeding takes place there as well as out- 
of-doors, especially during the autumn. 
VOL. I. 
F 
