THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
Up to 1899 some one hundred and twenty-two definite species of the 
Culicidae were described. Since that time many collections of mosquitoes have been 
examined from all parts of the world. Mr. F. V. Theobald, at the close of last year, 
as the result of an exhaustive examination of past works and new material, has 
remodelled the classification of the Culicidae^ which he has grouped into some twenty- 
two genera, and has described some one hundred and thirty-six distinct new species in 
his Monograph on the Culicidae of the World. To this number must be added some 
one hundred new species which he has not yet described. 
As yet only a few of the great number of mosquitoes have been investigated 
with regard to the important point of whether or no they can act as hosts for the 
malaria parasite. In fact only a few species of Culex have been shown to be incapable 
of transmitting the disease. 
When it was considered that not only malaria but other diseases were con- 
veyed by mosquitoes, for example, filaria can develop in two genera, Culex and Panoplites, 
and that yellow fever is certainly carried by one genus, Stegomyia, there arose a tendency 
to look upon all mosquitoes as harmful, and that their judicial destruction, as far as 
possible, was an object to be aimed at. How far this end can be attained is at present 
sub judice, but we have evidence that certain districts and towns lend themselves readily 
to this object. 
Experiments under this head are at present being carried on in West Africa 
and in Havana. On a smaller scale similar experiments have been carried out in 
Hong Kong and Statin Island, New York. Major Ross chose Freetown, Sierra 
Leone, for the scene for an experiment, to see how far mosquitoes can be diminished 
in a certain area, one ot the most difficult places on the West Coast to tackle. He and 
Dr. Logan Taylor, who was to direct the work there, arrived on July 2, 1901, and 
at once commenced the campaign against all varieties of mosquitoes. As yet the 
experiment is not completed, but a great diminution in the numbers of these insects 
has already been brought about. 
In Havana the work of exterminating mosquitoes, by the destruction of their 
breeding places, was commenced soon after the discovery that yellow fever could be 
transmitted by the bites of the common mosquito, Stegomyia jasciata. Major and 
Surgeon W. C. Gorgas, in his January report to the Military Governor, states that 
out of seventeen thousand houses examined during the month by the ' Stegomyia 
Brigade,' in four hundred and eleven only were mosquito larvae found ; the preceding 
January, larvae would have been found in all of the houses. Not only have the mos- 
quitoes diminished, but Havana has been for the last four months, October, November, 
December, January, entirely free from yellow fever. This result is certainly very 
encouraging when we compare the prevalence of yellow fever there during the same 
period of the previous year, when the average number of deaths from this disease was 
146-49. 
