Mosquito Annoyance at Blackheath . 59 
Donnington, Vanbrugh Road, 
Blackheath, S.E., 
8th April , 1902. 
To F. V. Theobald, Esq., M.A. 
Dear Sir,— Many thanks for your kind and interesting letter. I 
am writing the London County Council on the matter ol treating the 
ponds at Blackheath. I shall be greatly obliged if you will favour me 
with the modus operandi of using the petroleum, and if any particular kind 
is used, and where obtained. I presume it will destroy any fish that are in 
the pond ? -.it 
There are some Culices about now, but whether they bite or what, i 
know not. My opinion is, that the species that troubles us most in the 
summer are rather small, and I have noticed them settle but never 
appear to crawl ; whether that will prove what species they are I do not 
know. Thanks, I shall be very glad of the data you refer to of larval 
appearances. 
I suppose the enclosed large one is a Culex ; there are plenty in out- 
houses now. My opinion is, that the summer species is smaller. I have 
found a couple which were killed against the wall last summer. Are they 
Anopheles ? 
I am, etc., 
Walter Dannatt, F.E.S. 
British Museum (Nat. Hist.), 
Cromwell Road, S.W. 
To Walter Dannatt, Esq., F.E.S., Blackheath. 
Dear Sir, — As far as I can judge, the two remains of the Culicidae 
you send are those of Culex pip iens, the perfect one certainly is. No doubt 
the smaller one is Culex dorsalis , a very vicious biter. 
The usual times Anopheles maculipennis and different Culex larvm are 
found is in June, July, August and September. This would be the time 
to destroy the larvae, I fancy. A. bifurcatus, as I mentioned in a previous 
letter, occurs in the larval stage in winter also. They breed in rain 
barrels, small puddles, etc., so the work must be done very thoroughly. 
I should advise a look-out to be kept for the larvae before the paraffin 
treatment is started. 
The paraffin is best applied by dipping a bundle of rag tied on the end 
of a stick into the paraffin and then dabbing the pool over in many places, 
so as to get the whole surface covered with a thin film. I do not think 
fish would be hurt by the treatment, and doubt if you can get a better 
substitute at present for paraffin. I will find out from Dr. Daniels, who 
has bred Culex dorsalis , where they live. The only ones I have found 
were in a small puddle near a tap at Rochester. 
The paraffin treatment, I think, should be done two or three times at 
a week’s interval soon after the larvae are first noticed. 
I am, etc., 
(Signed) Fred. V. Theobald. 
