9 2 
THE DESTRUCTION OF MOSQUITOES. 
(To the Editor of The Times.) 
Sir: — Any suggestions or discoveries that help towards the destruction 
of mosquitoes and other insect pests in their larva stage are of such 
great importance that I venture to ask you to give me a small space in 
which to record some results which have been attained in the West 
Indies. 
It has long been known that Barbados is the only West Indian island 
that is absolutely free from malaria and from the presence of the anu- 
pheles mosquito. Major Hodder, B.E., in his reports to the War Office 
three years ago on the drainage works that were then being carried out 
in St. Lucia, came to the conclusion that there was some hitherto undis- 
covered reason why the anopheles failed to propagate its kind in Bar- 
bados where the culex was abundant. It appeared from his observations 
that the anopheles could, or did, only breed on the ground level; none 
of its larvae being found in tanks which were raised a few feet from 
the earth, nor even in those which were actually resting on the ground. 
The culex can, on the other hand, breed in the gutters on the roofs of 
high buildings as easily as in the low-lying swamps and pools. My friend, 
Mr. C. Kenrick Gibbons, w T ho had given a good deal of attention to the 
matter, pointed out at once that all the pools and swamps in this island 
were stocked with swarms of a tiny fish (known locally, from their vast 
numbers, as " millions "), and that their favorite food was the larvae of 
the mosquito. It is obvious that any species of that insect which is 
unable to breed above the ground level must fall a prey to this enemy. 
The fish has been identified by Mr. Boulenger, F.K.S., of the British 
Museum, as Girardinus pocciloides. Some specimens were successfully 
got to England, and flourished for some time in the insect house at the 
Zoological Society's Gardens. Mr. Gibbons' suggestion that the " mil- 
lions" should be imported into malarial districts in other islands has 
been acted upon, and with felicitous results. For instance, the Country 
Health Board of Antigua, " being convinced of the useful part played by 
these fish in consuming mosquito larvae, have arranged for their sys- 
tematic distribution throughout the ponds and streams of the island." 
Similar news comes from Jamaica, whither a consignment of the fish was 
sent in November, 1906. The secretary of the Agricultural Society 
writes that the tanks at the Titchfield Hotel are full of them, and that 
he had been informed that ' 1 there has been a marked diminution of fever 
round about, the ' millions' evidently accounting for the mosquito 
larvae." They have also been sent to Colon and to British Guiana. 
One cannot help wishing that these useful little fish were given a trial 
in the deadly districts of Africa, if, like the malarial mosquito, the in- 
sects which convey the terrible diseases which are endemic there, pass 
the larva stage of their existence in water. One may add in this con- 
nexion that the Swedish Consul at Frankfort has discovered a small fish 
("the blue-eyed") which feeds on mosquito larvae, and that, at the 
request of the Italian Government, some are to be, or have been, sent 
to the Campagna, where so much has been done in recent years to dimin- 
ish malaria. 
I am, Sir, your obedient servant, 
T. HEBBEET BIXDLEY. 
Codrington College, Barbados, March. 
"Times," London, April, 1908. 
