12 



The Philippine Journal of Science 



1918 



Most of the data found in Table II require little comment 

 and will be summarized in connection with the species summary 

 at the end of this paper. It may be noted, however, that of 

 species that include a fair number of dissections ludlowi, ma- 

 culatus, and kawari have relatively high percentages infected. 

 Anopheles aconitus is also high, but the numbers are few. The 

 brackish-water indefinitus is well above the fresh water, but both 

 are below 1'ossi type Giles. Anopheles barbirostris and sinensis 

 rank low in percentage infected. Anopheles ludlowi, rossi type 

 Giles, aconitus, and kawari show the more-marked tendency to 

 form sporozoites in the salivary glands. Anopheles umbrosus 

 may be included under those readily forming sporozoites, al- 

 though the specimens with sporozoites in the salivary glands had 

 been caught in the imago stage and may have been infected be- 

 fore feeding, since other specimens taken at the same time and 

 from the same locality showed sporozoites, although not exposed 

 to a gamete carrier. Anopheles indefinitus showed no sporo- 

 zoites in the salivary glands, although fair numbers of the 

 brackish- water type were dissected. Anopheles maculatus was 

 largely used as a control, and none were dissected till ten days 

 after feeding on the gamete carrier. The number of specimens 

 of different species showing sporozoites in the mid-gut is in- 

 cluded in the table, since the proportion of these gives us some 

 indication of the probability that a species may under some 

 conditions form sporozoites in the salivary glands. 



Many cages, including many dissections, were done that 

 are not included in Table II, since in these there was no control 

 to show that the gametes were viable at the time of feeding. 

 The relative numbers of controlled and noncontrolled cages and 

 dissections are given in Table III. 



Table III. — Comparison of controlled and noncontrolled series. 





Controlled. 



Noncontrolled. 



Cages - - 



108 

 1,103 



Per cent. 

 49.8 

 53.2 



Ill 

 969 



Per cent. 

 BO. 7 

 46.8 







In a large proportion of the experiments the blood of the 

 gamete carrier was examined on the day of feeding and usually 

 at the time of feeding. In a small proportion of cases the 

 carrier was examined on the day preceding or the day following 

 feeding. No carrier was used, in crescent carriers at least, 

 who did not have a sufficient number of gametes to infect, or 1 



