394 MOSQUITOES OF NORTH AMERICA 
which require more or less attention from three men during most of the open 
season. They keep the ditches clear, supplementing their work by judicious 
oiling here and there wherever mosquito larve are abundant and then have con- 
siderable time available for perfecting the system and ditching more distant 
marshes. Experience showed that a considerable number of salt marsh mos- 
quitos bred on that portion of Jamaica bay northwest of the village were 
brought in by southwest followed by northeast winds. This led to the extension 
of ditching operations some 2 miles beyond the village limits. The work in the 
immediate vicinity of Lawrence was done partly at public expense assisted by 
contributions from owners benefited, though it was impossible to secure the co- 
operation of persons owning the distant marshes, which latter were drained 
entirely at village expense. The existence of such breeding areas is an imposi- 
tion upon adjacent communities and it is only a question of time before public 
opinion will demand a law either compelling owners to abate such nuisances or 
else provide for their suppression at public expense. The money invested by 
Lawrence in this work, a total of less than $10,000, has amply justified itself in 
vastly improved conditions. The village and its vicinity have been entirely freed 
from breeding places, though occasionally it is subject to late summer invasions 
by hordes of mosquitos when favorable winds bring them from undrained 
marshes. Even this will be obviated when the value of the work becomes more 
generally appreciated and then the cost of the operations will be amply returned 
in increased land values, to say nothing of the satisfaction accruing from the 
absence of these dangerous and annoying pests.” 
On the north shore of Long Island, in Connecticut, and especially in the 
vicinity of New Haven, certain simple ditching operations have been carried on 
which have resulted, at a comparative small expense, in a very considerable 
reduction of the mosquito supply. 
In California, in connection with work carried on by the California State 
Agricultural Experiment Station, in 1905, some excellent work was done under 
the auspices of the Burlingame Improvement Club, in San Francisco, under the 
direction of H. J. Quayle, of the Experiment Station. The territory involved 
is included in the upper portion of the San Francisco peninsula, extending from 
south San Francisco on the north to San Mateo on the south, a distance of about 
10 miles. The salt-marsh area included consisted of a narrow strip along the 
San Francisco Bay shore, varying from } to 2 miles in width, and 10 miles long. 
No part of the area was continually covered with water, and it is all above the 
lowest high tide. The higher tides, however, particularly those accompanying 
full moon, almost completely submerge the area and result in the development 
of large broods of salt-marsh mosquitoes. The operations are described as 
follows: 
“The actual work of control was commenced February 27th, when a gang of 
men was started to work at ditching on the salt marsh. This work was started 
near the Blackhawk dairy, where the marshes begin north of Burlingame, it 
being the intention to work northward toward San Bruno, and make the work 
permanent as far as we would be able to go in a single season. However, the 
work went rapidly and the troublesome areas north of Millbrae were not so 
numerous as was figured, and consequently practically the whole area was 
covered during the past season. 
“The ditching in the Blackhawk area consisted in connecting the pools and 
areas of standing water with the tidal creeks in order that they might drain 
