224 The Philippine Journal of Science 1915 
TABLE VIII.—“Ditch” or “canal” towns—Continued. 














No. | 
ae Name. General surroundings. Ditches. pa is eeriats 
| VI. 
16 | Nagearlan___._____ Billy) So ae ee Many laterals; clear water;| Brook near | 
flow swift with quieter | town. 
places. Somevegetation. | 
AS isucbanes sce = Mountain; elevation, | Many laterals; clear water; | Brook in town. 
425 meters. swift. Little vegetation. 
AON etayabis esse irllytoaseae ree see Many laterals; clear water;| Brook near 
mostly swift, but with town. 
quiet places. Some 
vegetation. 
50) | '‘Sariayase sees Hilly; elevation, 195 | Not many laterals; mostly |____________________ 
meters. swift. Some refuse veg- 
etation. 
Malarial survey. 
No. j 2 
Tabl Anopheles survey. | Perernae PUES 
vi a! ee 
s Parasite.| Spleen. 
2| A. rossi in ditch. A. rossii and A. bar- nee 18, 1914 52 0.0 0.0 | 
birostris numerous in river. Aug.  6,1914 116 | 0.0 0.0 
ane ; ’ Apr. 30,1914 | 54| 20.0 7.4 
9 | A. febrifer in ee of walls of ditches, |e 19, 1914 | 50 | idiot fea 
also elsewhere in ditches andin brook. = || apainases 150 ieee | L7 
: bet _ |Mar. 28, 1914 | 137 19:0} |-==eeeee 
10 | A. febrifer EERO Ue GHG R2E also in July 22,1914 | 18 57.8 | 39.1 
bropke: A. sinensis (?) in ditch. A. ros- | Oct.-Nov., 1914 | avi gpg) eee 
SULT DOOLS: bp Bg a oe Ue el oe lice douhitne pop | eae seks 70.9 
erat _ |{Mar. 31,1914 | 49 | 8.2) ene 
15 | A. febrifer in ditches and numerous in jase 18,1914 | 51 $5.5 |< eee / 
DIRS. i cae Yea te | gag]... See 
(Apr. 29,1914 | 58; 115] 94 | 
16 | A. febrifer in ditches and in brook -_-_-_---- fav 20, 1914 } 52 22:9) | ae . 
eat dome 112 |. eran 
48 | A. febrifer in brook. None found in| Dec. 11,1914 112 3.6 14.4 ) 
ditches. January 7, 1915. | | 
49 | A. febrifer in ditches _____-..--.------------ Dec. 10, 1914 10/ 29.1) 82.7 
50 | A. febrifer in ditch in alley ---_--------_.--- Jan, 8, 1915 29 | 4.4 | 51.7 


® Slides not in best condition for examination. 
The parasite index of all these towns is relatively high with 
the exception of Calamba, Lucban, and Sariaya. Calamba af- 
fords a case of especial interest. One long ditch runs through 
the main street of the town, and a few laterals extend from it. 
Quiet places suitable for the breeding of Anopheles febrifer are 
plentiful, but the water in the ditch comes from rice paddies 
and is comparatively warm and foul. A long search for larve 
