PROPHYLAXIS OF MALARIA. 
51 
is of great importance in the prophylaxis of malaria. It is more 
than probable that much longer distances can be covered by inter¬ 
rupted flight, and that the anophelines are not an exception to the 
rule that mosquitoes will fly for great distances in order to reach 
their food or their breeding places. 
Breeding places .—Contrary to our older notions regarding the 
breeding places of anophelines we now know that these mosquitoes 
may breed in practically any collection of water, even though there 
be quite a current present. Watson 22 , in the Federated Malay States, 
found that N yssovhynchus willmori will breed in mountain streams 
where the current is swift, and that the larvae of this species is capa¬ 
ble of swimming against the current of these streams. As a rule 
the anophelines prefer to breed in comparatively clean water, as 
that found in slowly running streams or in pools of rain water, 
but they will breed in foul water and have been found in sewers. 
Paddy fields, storage tanks, wells, ditches, ponds, gutters, drains, 
and springs are all favorite breeding places of anophelines, gome 
species preferring one place and some another. As Theobald states: 
Practically all kinds of collections of water are acceptable to the larvae; 
some prefer rain-water barrels, cisterns, and the water in tins, calabashes, 
and jam pots; others ponds, slow running streams, and along the banks of 
large rivers: others live in the water collected in bromelias, and in the water 
that collects in hollow bamboos, gaining their entrance through exit holes 
left by boring insects. The domestic species which are best known usually 
choose barrels and cisterns. 
In the Philippines a favorite breeding place of anophelines was 
the cavity left after cutting off bamboo poles near a joint. In the 
latter part of the rainy season I have found larvae in nearly every 
bamboo pole examined, and at Camp Stotsenburg, where temporary 
quarters for a large number of troops were built of this material, 
anophelines became a veritable scourge and malaria increased to 
such an extent that it was found necessary to remove the larger part 
of a brigade which had been stationed there. 
Among the breeding places of anophelines which are most likely 
to be overlooked may be mentioned the small depressions in the 
ground produced by the hoofs of animals or the inequalities left in 
plowed land. In the tropics, during the rainy season, such breeding 
places are sometimes very numerous and furnish a considerable pro¬ 
portion of the mosquito population. Another source of mosquitoes 
nenerallv overlooked is the water that collects at the bases of the 
leaves of certain plants, especially the Bromeliacece. Lutz 23 found 
Anopheles cruzii breeding in the water collected by the leaves of 
these plants and other observers have confirmed his results. 
It has also been determined that some species of Anopheles will 
breed in brackish or salt water. Among these species may he men- 
