42 ' 
A Monograph of Culicidae. 
From such information, received from all parts of the world, 
the verdict must be that Anopheles can and do breed almost 
anywhere where the flow of water is not too rapid, not only, 
as Colonel Giles says in his MS. notes sent me, near human 
habitations, but also far away from them. How is it possible, 
then, to destroy even an appreciable amount of the larvae ? 
Anyone who has a practical economic entomological knowledge 
will know the extreme difficulty of keeping the many plant 
pests in check, much less extirpating them. This is because 
they often breed over a wide area, in woods and forests, and from 
thence attack our crops. The hop grower would stand some 
chance in England of destroying the hop-aphis by repeatedly 
spraying all the wild prunes in all our woods for a few years. 
Think what that would mean. Certainly financial ruin to all 
the growers. Theoretically, Anopheles could be stamped out by 
spraying all the water with paraffin, but when we recognise the 
enormous and varied area over which thev breed, the absolute 
hopelessness of the task is at once apparent. Possibly malaria 
may be lessened by destroying the breeding-grounds of Anopheles 
around habitations and especially by paying attention to surface 
drainage. * 
V , 
Culex larvae. —The larvae of Culex not only differ in struc¬ 
ture, but also very markedly in habits. Instead of almost exclu¬ 
sively inhabiting natural collections of water, they are particularly 
predisposed to water in artificial receptacles. In England, water- 
butts, cisterns, disused pots full of water, &c., are the favourite 
places for the larvae of many species, such as Culex pipiens and 
C. nigritulus. I have bred the latter species from the foulest water 
possible in old manure barrels ; but the former seems to prefer 
clear water, teeming with minute animals and desmids. Like 
Anopheles , however, they prefer water of no great depth, and 
with more or less small animal and vegetable life in it. I have 
observed them in deep water once or twice in the Cam, but such 
is unusual, as also is it to find them where there are fish. Dr. 
Bancroft and Ficalbi both record the larvae of Culex in salt water ; 
the former four species, including the new C. marinus , mihi, the 
latter one, C. salinus (Ficalbi). 
Dr. St. George Gray, in one of his previously quoted letters, 
reports that he found Culex larvae in similar places to the 
Anopheles. 
Captain James, writing of the “ Filaria carrying mosquito,” 
