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THE RELATION BETWEEN THE HATCHING OF 
THE EGGS AND THE DEVELOPMENT OF THE 
LARVAE OF STEGOMYIA F ASCI AT A {AEDES 
GALOP US), AND THE PRESENCE OF BACTERIA 
AND YEASTS. 
By E. E. ATKIN and A. BACOT, 
Of the Lister Institute of Preventive Medicine. 
Introduction. 
The clearing action of mosquito larvae in turbid water and their 
scarcity or absence in clean water, is an old-established popular belief 
in mosquito ridden districts of both the old and new world. If the 
presence of certain species of .Anopheles larvae in clear running water, 
where they doubtless feed on algae, be excepted, it is probable that 
this general observation is in the main correct. The fact that numbers 
of mosquito larvae are frequently present in the small collections of 
clear water which occur in the cut ends of bamboos, the axils of leaves, 
or the smaller rock or root pools, is an apparent but not a real contra¬ 
diction of the correctness of this popular belief, because in these instances 
one of two possibilities may have occurred. Either the large number of 
dormant eggs which hatched when rain first filled the receptacle was 
sufficient to check and control bacterial or yeast development from the 
start, or, as is more likely in the case of root or rock pools, the turbidity 
due to bacteria or yeasts had been rapidly cleared as the rapacity of the 
quickly growing larvae increased beyond the source of nutriment. 
Mitchell (1907), referring to Stegomyia fasciata, says it is pre¬ 
eminently a bacteria-eating “wriggler,” presumably on the strength of 
the known fact that the larvae develop rapidly in sewage-contaminated 
water. 
Howard, Dyar, and Knab (1912) mention bacteria as forming food 
for mosquito larvae in general terms, stating that the spores of algae, 
particles of dust, bacteiia, protozoa, minute aquatic animals of many 
different kinds are swallowed. They specifically mention that the 
