194 The Philippine Journal of Science 1916 
it is very easy to overlook mosquitoes when they are concealed 
in the daytime, and it is possible that a large proportion of the 
stronger larve emerged and reached safety. 
Similar negative results were obtained in a comparatively 
short search for mature anopheles in Magdalena, Laguna Prov- 
ince, where A. febrifer larve were plentiful and malaria very 
prevalent. 
It is possible that certain meteorological conditions favor 
the dispersal of this species of anopheles as well as that of other 
species. In Mindoro, where many anopheles imagoes were found, 
the weather was hot with frequent afternoon showers. At 
Iwahig, where many mature A. febrifer were caught, the tem- 
perature was comparatively low for the tropics and the humidity 
great. At Negros, where negative results were obtained, the 
weather was hot with occasional showers, not unlike that of 
Mindoro at the time of our visit there. At Magdalena it was 
hot and dry. However, the facilities for obtaining mature 
anopheles were much better at Mindoro and Iwahig than at the 
other localities examined, and it is probable that a search con- 
tinued over some time and during a variety of meteorological 
conditions would reveal the lurking places of any anopheles in a 
locality where their larve are found in any number. 
In the Philippines, as well as in other places where observa- 
tions have been made, anopheles usually remain hidden during 
the daytime. During many days of work in shady woods and 
canons we have observed anopheles flying by day on only one 
occasion, when a specimen of A. barbirostris settled on the hand 
at noontime on a cloudy day in a narrow cafon. The mosquito 
filled its stomach with blood and expelled a drop from the anus. 
The specimen was caught and taken to the laboratory for dis- 
section and identification. : 
Owing to a lack of time a comparatively small proportion of 
the mature anopheles caught at Mindoro and Iwahig were dis- 
sected and examined for malarial parasites. Moreover the 
relative’ infectivity for malarial parasites had already been de- 
termined for all the species obtained in these places. All 
dissections that were made were negative. In Mindoro, where 
mosquitoes were caught in houses almost daily, the chances of 
finding an infected one were probably small. In some Panama 
barracks, where a daily routine of catching anopheles was prac- 
ticed, Darling’ reports that only one naturally infected mosquito 
was found in about 500 dissected. 
"Proc. Canal Zone Med. Assoc. (April, 1909, to March, 1910). 
