Mosquito Annoyance at Blackheath. 59 



DONNINGTON, VaNBRUGH ROAD, 



Blackheath, S.E., 



Wi April, 1902. 

 To F. V. Theobald, Esq., M.A. 



Dear Sir, — Many thanks for your kind and interesting letter. I 

 am Avriting the London County Council on the matter of 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 ? 



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 Cidex ; 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 pipiens, the perfect one certainly is. No doubt 

 the smaller one is Gidex dorsalis, a very vicious biter. 



The usual times Anopheles macidipennis and different Cidex larvae are 

 found is in June, July, August and September. This would be the time 

 to destroy the larvae, I fancy. A. hifarcatus, 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 larvte before the parafl&n 

 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 Gidex dor sails, 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. 



