464 SCIENCE PROGRESS 



fever. These epidemics were, however, speedily suppressed owing to the 

 fact that, under war conditions, the necessary measures of mosquito control 

 could be of&cially enforced as well as ofiSicially financed.^ 



(ii) The prevalent fallacy regarding the twenty-two " non-malarial " 

 English mosquitoes as " perfectly harmless " is somewhat surprising, in view 

 of the fact that throughout every summer and autumn various forms of 

 " blood-poisoning " admittedly arising (however indirectly) from the bites of 

 these insects are of constant occurrence in every town and village in the 

 country. The following statement by Professor Lefroy, of the Imperial 

 College of Science and Technology, South Kensington, an eminent authority 

 on entomology, was published in TJie Times on September 9, 192 1 : 



" During this year there have been quite an abnormal number of deaths 

 from either wasp-stings or the bites of the brown mosquito (which does 

 not convey malaria), or from the bites of flies which have not been identified. 

 To some extent this has been due to the fact that the heat and dry con- 

 ditions have led these insects to attack man more freely ; but we are ignorant 

 of the reason why the bite of a harmless brown mosquito can cause death 

 within two or three days, when we know that no specific disease such as malaria 

 has been introduced. It is extraordinary that coroners should pass verdicts 

 of " Accidental Death " in such cases without emphasising the need of 

 investigation into the actual cause of death when a healthy person has been 

 bitten by such an insect as a common brown gnat or mosquito. This is a 

 subject which undoubtedly requires investigation, and yet is tacitly accepted 

 as the cause of death in quite frequent cases." 



(iii) To demonstrate the inaccuracy of the third " popular belief " (that 

 it is impossible to minimise the annoyance caused by mosquitoes in a given 

 district) a mass of conclusive evidence has been collected from all parts of 

 the world. It is to be hoped that amongst this evidence a place may eventu- 

 ally be found for the results achieved by the Hayling Mosquito Control, the 

 first " unofi&cial " organisation of the kind in England, a brief description of 

 w^hich is given below. 



• • • • • 



The formation of the Hayling Island scheme was not definitely resolved 

 upon until the autumn of 1920 (a more than usually bad " mosquito year " 

 both in England and on the Continent), when it was too late to attempt 

 anything in the way of active anti-mosquito operations. During the month 

 of September, however, a large number of mosquitoes were caught, and their 

 subsequent identification (by means of Dr. Lang's admirable Handbook of 

 British Mosquitoes) showed them to be almost entirely of three "non- 

 malarial" kinds, namely : (i) the common brown " domestic " mosquito, Culex 

 pipiens; (2) the large " banded-legged " mosquito, Theobaldia annulata; and 

 (3) the " salt marsh" mosquito, Ochlerotatus detritus.^ That these were the 

 prevalent species of the district was confirmed by the observations of the 

 following year. 



The mosquito Ochlerotatus detritus (which is extremely common all 

 round the English coast) is generally described as breeding in " brackish " water. 

 This, however, seems to be a rather mild way of stating the case, seeing that 

 the writer has frequently found the larvae in enormous numbers, not only in 

 stagnant sea-water of " full strength," but also in sea-water which, through 

 evaporation, has been found (by titration with silver nitrate) to be of super- 



^ See Local Government Board publications, Reports and Papers on Malaria 

 Contracted in England in 1917 (published 1918), and Reports and Papers on 

 Malaria Contracted in England in 1918 (published in 1919). 



2 The prevalence of the last-named mosquito had been predicted by the 

 well-known authority Mr. F. W. Edwards, of the British Museum (Natural 

 History), to whom the writer is indebted for very much advice and help. 



