ILLUSTRATIONS 
PLATE I 
Fic. 1. A stream flowing through Bongabon, Nueva Ecija Province, Luzon, 
a town with a high malarial index. Ancpheles febrifer is abun- 
dant along both margins of this stream, wherever vegetation or 
indentations in the bank afford shelter. 
2. Baliuag River, Nueva Ecija Province, Luzon. A bridge-construction 
camp, where there was a severe outbreak of malaria in 1912-1913, 
was located on the bank at the right of the picture. Larve of 
Anopheles febrifer were found in the grass at the margin of the 
stream at the right. 
PLATE II 
Map of Magdalena, Laguna Province, Luzon, showing the results of a mala- 
rial survey of the town. 
TEXT FIGURE 
Fic. 1. Diagram, showing the relative abundance of the larve of four species 
of Anopheles in habitats arranged according to the amount of 
decaying organic matter in solution in the water. 
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