Mosquito Control.

Scientist Says Megarhinus Is of No Value.

WE are informed by the Minister in Charge of Territories (Major Marr) that Mr. F. H. Taylor, Entomo logist of the School of Public Health and Tropical Medicine, University of Sydney, has furnished a report on the result of the recent investigations car ried out by him in Rabaul, concerning mosquito control in the Territory of New Guinea.

Mr. Taylor’s enquiries were particu larly directed to the question whether and to what extent the larvae of Megarhinus inornatus would check or help to check the breeding of the larvae of malaria-carrying mosquitoes, Anopheles punctulatus, and of its variety, moluccanais. (“Megarhinus” is a parasite mosquito, whose larvae attacks and destroys the larvae of other kinds of mosquitoes).

As a result, Mr. Taylor considers that the larvae of the Megarhinus would be of little use in the destruction of the Anopheles larvae. Mr. Taylor reports that there are fewer mosquitoes in Rabaul than he has seen in any town in Australia, from Thursday Island to Adelaide. Excellent results, he states, are being obtained in dealing with the mosquito by the use of the larvivorous fish, Gambusia affinis.

The field observations and laboratory experiments carried out by Mr. Taylor in Rabaul demonstrated that Megar hinus inornatus is of no value in the control of Anopheles mosquitoes, and that the methods adopted by the New Guinea Administration —i.e., the use of Gambusia affinis (larvivorous fish), or Paris Green—together with general sanitary and engineering measures, are on sound lines and are giving success ful results in controlling mosquitoes.

Editorial Note.

This investigation was forced on a reluctant service by action taken by Mr. W. R. Carpenter, who brought the matter before the Sydney Chamber of Commerce, by which body it was re ferred to Canberra.

The Megarhinus was discovered several years ago. An American entomologist expressed the emphatic opinion that it might be propagated and used to destroy the larvae of the Anopheles mosquito, which carries malaria fever throughout the Territory.

The Territory medical service ridiculed the idea.

Various people insisted that the plan should be investigated. Mr. Carpenter offered personally to bear the whole cost of a thorough investigation and experiments. The medical service was unsympathetic, if not hostile.

If the statement issued by the Minister is a fair summary of Mr.

Taylor’s report, it is ludicrous, and indicates that Mr. Taylor’s “investiga tion” was a waste of money.

The chief questions at issue were whether the parasite mosquito, which. is now naturally propagated in tree water, could be adapted to breeding in ground-water, where it would find and attack the Anopheles; and, if so, would it be practicable to introduce the Megarhinus to other parts of the Ter ritory, from its habitat near Rabaul?

These questions appear to have been left severely alone. That is not sur prising. The scientific gentlemen con cerned, right from the first, have shown determined opposition to any interference or suggestions.

No one has ever questioned the value of the work being done by the New Guinea medical service, nor its remark able success in eradicating malaria from Rabaul and other well-settled places. What is wanted is some means of combating malaria in other parts of the Territory, where the fever is rampant, and the methods which have been so successful in Rabaul, etc., can not be employed.