SEA-WATER BREEDERS 227 
the mountain province of Lepanto-Bontoe for the purpose of investigating an 
epidemic of malarial fever. He fully expected to find that the responsible mos- 
quito would prove to be a different species, but during his first stay in the 
province he found what he considered Anopheles ludlowii in the dwellings, 
while later he also found their larve breeding in greatest abundance in the 
rivers and smaller streams of the vicinity. He spent over two weeks in the 
neighborhood, and made a search for larve which included the rice fields 
(flooded at that time of the year), the water tanks near the buildings, and all 
probable breeding-places. He states that he found no other species of Anopheles. 
It is evident that the observations of Mr. Banks are faulty and inconclusive. 
From the observations previously cited it is to be seen that Anopheles ludlowu 
breeds exclusively in saline water. The species which he found at Lepanto- 
Bontoe and so identified was in all probability Anopheles rossi. However, as 
this latter species is known to be ineffective as a malaria transmitter, and as other 
species of Anopheles have a wide distribution in the Philippines, it is obvious 
that his methods were inadequate. Moreover, it appears that many of the de- 
terminations were made from larve and were therefore unreliable, as the 
Anopheles larve are very similar and much more difficult to distinguish than 
the adults. 
Some interesting observations on the existence of Anopheles larve in sea-water 
were made by Dutton in his malaria expedition to the Gambia in 1902 (Liver- 
pool School of Tropical Medicine, Memoir X). The following account is taken 
from pages 29 to 30 of his report: 
“A garden tub in which mosquitoes had been breeding was emptied and 
cleaned, and sea water, taken as the tide was coming in, placed in it, the other 
tubs in the garden being covered with mosquito netting. In four days afterwards 
a batch of small Anopheles larve was discovered in the water, which subsequently 
hatched out into adult mosquitoes (A. costalis) seven days later. This experi- 
ment was repeated with the result that first eggs of Anopheles and also Culex 
appeared in one or two days after the tidal water had been placed in the tub, 
and subsequently adult insects hatched out from them. From these experiments 
it would thus appear that certain kinds of mosquitoes can breed in tidal water if 
it is not disturbed, and subsequently when the dry season had fully set in, I 
found larve in suitable tidal pools, namely, as J have already mentioned, in the 
drains near the sluice gates in which tidal water had soaked in through the 
gates. In this water, which contained 1038.5 parts of chlorine per 100,000 parts, 
I found a few larve of A. costalis and large numbers of Culex halassios. On 
another occasion, in December, I found these mosquitoes breeding in a small 
hole from which shells had been taken, close to the edge of the water at the 
mouth of Oyster Creek. The Culex were subsequently hatched out from this 
tidal water, but the Anopheles larvee were nearly all infested with a fungus (not 
identified) which gave them a woolly appearance, and I failed to hatch out any 
of them. I observed A. costalis breeding in a similar salt-water pool during a 
period in which neap tides occurred. The tidal water in an arm of the central 
channel in Box Bar, running from the sluice gates to the cemetery, had become 
converted into a series of small pools by partial evaporation of the water, though 
at every tide some water leaks through the sluice gates into this channel, but 
during this period it was not sufficient to replenish this small branch drain. 
Anopheles larve were found in great numbers in these pools. It is interesting 
16 
