186 OBSERVATIONS ON CULEX PIPIENS. 
I bred out several adults, and sent a male and female to the 
Dumfries Museum. 
My article in the Dumfries and Galloway Standard 
elicited some remarks from the Editor and correspondents, 
\which seem to indicate the common occurrence of mosquitoes 
in large numbers in the neighbourhood of Castle-Douglas and 
elsewhere in the county. 
Later in the year I found this same species on the wing 
in Broxburn, near Edinburgh, and in Tow Law, in Durham 
County. In the latter place I was succssful in finding, in a 
moss pool into which stable wash drained, a number of larve, 
from which I bred several adults. 
A tropical congener of pipiens, known as C. fatigans 
(quinque faciatus Say), is a carrier of filaria, and mosquitoes 
of the same group are known to be the intermediate hosts of a 
number of spirochaltes, some of which are of pathological 
importance. The presence of these insects is therefore always 
of interest, and, when sufficiently numerous, it only requires 
the simultaneous presence of an organism noxious to man or 
beast of which they may be intermediaries to raise them to 
the status of dangerous enemies to his comfort and well-being. 
It is therefore desirable that attention should be given to their 
occurrence and frequency, and to the places where they breed, 
even in times when their numbers are comparatively insignifi- 
cant, so that any dangerous multiplication may be dealt with 
promptly should the need for steps to suppress them be demon- 
strated or suspected. The habitat of the larvee of the Culex 
species, where preventive measures should begin, is indicated 
in the character of the breeding places described in this paper. 
Collections of foul water not far from dwelling-places are the 
first which should be inspected and dealt with, either by demo- 
lition or, if that is inconvenient, by spraying with oil at inter- 
vals of seven days. It may be generally said that the occur- 
rence of numerous small collections of water is more favourable 
to the multiplication of this mosquito than a few large col- 
lections. The Anopheles differs in its selection of a breeding 
place in so far that it prefers clean water. The presence of . 
alge is favourable to its multiplication, however. In larger 
sheets of water it may be found developing successfully in the 
