BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 57 
habits of this fly along the coast of Florida disclosed that prolific breeding takes 
place in decomposing piles of Sargassum sp., a brown marine alga. Destruction 
of such breeding places would decrease the abundance of the fly. 
AUSTRALIAN CATTLE TICK 
Experiments carried out cooperatively with the Bureau of Animal Industry 
and the Florida Livestock Sanitation Commission on the Australian cattle tick 
(Margaropus annulatus australis Fuller) confirm the field observations that 
deer serve as an effective host of this tick. Apparently, however, there is greater 
individual and seasonal variation as to the number of ticks reared than in 
the case of the more normal bovine host. 
BLACK FLIES OR BUFFALO GNATS 
An outbreak of black flies (Simulium sp.) during the spring of 1935 in 
Arkansas and Louisiana, especially in the Mississippi Delta area, caused con- 
siderable injury and some deaths in livestock. An interesting discovery, and 
one which may have a definite bearing on finding some method of controlling 
these injurious insects which have heretofore been more or less immune to con- 
trol procedure, was made during the winter of 1934. It was found that under 
laboratory conditions eggs undergo a period of aestivation for as long as 8 
months. Under field conditions the eggs are washed into river cut-offs and 
bayous, where the stagnant water is unfavorable for development. The advent 
of subsequent floods and the consequent agitation of the water where the 
eg.£s have remained dormant produce ideal conditions for the emergence of 
enormous numbers of the adult gnats. 
EYE GNATS 
Observations on the biology and abundance of eye gnats in the Winter 
Garden section of southwestern Texas were carried on throughout the year. 
In June of the current year a representative of the Bureau was sent to assist 
in the reorganization of the gnat abatement district of Coachella, Calif., where 
the residents were anxious to continue the control measures recommended by 
the Bureau. 
MOSQUITOES 
Much assistance has been rendered by the Bureau to various local. State, 
and Federal agencies in making mosquito surveys, and waging control cam- 
paigns in the States of South Carolina, Georgia, Florida, Alabama, Oregon, and 
Washington. 
In the Southeast, mosquito surveys, with recommendations as to suitable con- 
trol methods, were made at Parris Island, S. C, in cooperation with the United 
States Marine and the Naval Medical Corps: at Savannah, Ga., and York- 
town, Va., in cooperation with the National Park Service; and at Roanoke Is- 
land and adjacent territory on the North Carolina banks. Studies of the salt 
marshes and salt-marsh mosquitoes of Florida have been carried out during 
the year, and assistance has been given to county organizations, the S 
board of health, and the Emergency Relief Administration in mosquito-control 
problems. In the control of Aedes aegppti L., considerable help was given to 
several towns and cities in Florida which suffered an outbreak of dengue fever. 
Mosquito-control activities in the Northwest consisted principally in dire 
projects in Multnomah County, Oreg., under funds allotted by S. E. R. A. and 
the city of Portland; and in the Columbia National Forest in cooperation with 
the Forest Service of the North Pacific region. 
Experimental work has been carried out to test the effectiveness of mosquito 
larvicides and methods for controlling Mansonia pert urban* Walker and other 
species in Florida, and Aedes aldrichi D. and K.. A. vexans Meig., and Che 
so-called "snow-water" species in the Pacific Northwe r. 
Investigations have been carried on. in cooperation with the Pathological 
Division of the Bureau of Animal Industry, on the transmission of the fatal 
malady of horses known a> "equine encephalomyelitis" by mosquitoes. It 
has been shown in numerous tests that the yellow fever mosquito, Aedes 
aegypti, is an efficient carrier of the western strain of the disease, bin a very 
poor carrier of the eastern strain. The only instance in which the eastern 
strain was transmitted from an infected to a healthy guinea pig was in the 
