Mosquito Control.

“Megarhinus” Is Proved To Be Useless.

AT different times, in past months, we have criticised the Health Department in New Guinea for its seeming indifference towards the pos sibility of introducing a new factor in malaria-control operations there.

The facts are: Malaria fever is general throughout New Guinea, and its economic cost is enormous; many methods of attacking the anopheles mosquito (carrier of malaria) have been studied; Mr. C. B. Pemberton, an American entomologist, was in Rabaul some years ago, and discovered a kind of mosquito, Megarhinus Inornatus, whose larvae attacked the larvae of the Anopheles; it was found, however, that Megarhinus lives in water in trees, while the Anopheles breeds in ground water; it was suggested that efforts be made to adapt Megarhinus to ground-water conditions, so that he might regularly feed on Anopheles larvae.

When, last year, inquiries were made about the matter, one got the impres sion that the health Department treated the subject with lofty scorn —which is too frequently characteristic of the attitude of the scientist towards the in terfering layman. Whereupon, we were outspoken.

However, the wheels of officialdom have been moving, after all, and we are very glad indeed to receive and pub lish the following correspondence.

The Federal Director-General of Public Health (Dr. J. H. L. Cumpston) writes from Canberra under date 25th July; “With reference to your article headed “Mosquito Control.” in the issue of the ‘Pacific Islands Monthly,’ 24th June, 1933, I attach a copy of a letter from Mr. C. B. Pemberton renting to the subject matter of the article in question “It is suggested that in justice to this Department and the officers concerned, the purport of Mr. Pemberton's com munication might be published. Mr Pemberton is the American entomologist referred to in your article.”

Mr. C. E. Pemberton, executive entomologist, writes from the Experi ment Station of the Hawaiian Sugar Planters’ Association, Honolulu, Ha waii, on October 29, 1932, to Dr. Harvey Sutton (Director, School of Public Health and Tropical Medicine, Univer sity of Sydney), as follows: “I have your letter of 29th Septem 1932, with enclosures, covering the

subject of Megarhinus inornatus in its relation to Anopheline mosquitoes in New Britain, “The statement by Dr. T. Clive Back house, which you enclose, is a correct summary of the whole question, in my opinion.

“The lay Press reports of my work were very much distorted. I do not be lieve mosquitoes of the genus Megar hinus can ever be of any use against other species whose larvae occur in ground pools, nor do I believe it possible by artificial means to produce a strain of any species of Megarhinus that could be induced to alter its habits sufficiently to place its eggs in such situations.

“I introduced Megarhinus inoratus to Hawaii in an effort to establish some check on two species of mosquitoes here which breed in our forests in tree holes and rock pools adjacent to the towns.

The species went through several gene rations after liberation in one forest locality here, and then completely died cut. I have published nothing on the subject.

“From my observations about Rabaul it appeared practicable to control Ano pheline mosquitoes by careful and in tensive drainage and oiling of all ground water, no matter how small, at all points within a few hundred yards of habita tions.’’

That seems to be the final word on the interesting subject of Megarhinus.

The creature appears to be a com plete “wash-out.”

It is a matter for regret that Mr.

Pemberton’s letter was not made avail able for publication at the end of last year, seeing that it deals with a subject of much public interest.