213 
Chlorine Contents of Natural Waters in which Mosquito Larvae have bf.en taken, 
AND IN SOME INSTANCES BRED OUT 
A. pseudopunctipennis 
Ce. albimana 
Anopheles (Sp.) 
Ce. albimana 
Ce. albimana 
Are. (?) malefactor... 
Ce. albimana 
Arr. (?) malefactor ... 
Ce. albimana 
Ce. tarsimaculata ... 
Ce. albimana 
A. pseudopunctipem 
Stegomyia calopus 
Culex (Sp.) 
Aedes taeniorhynchus 
Per cent, of Sodium Chloride 
0-00165 
'•93 
0-65 
1- 165 
0-255 
0-16 
o-i 6 
0-00002 
0-00125 
o- 16 
0-21 
0-63 
1-02 
0-02 
0-02 
0-26 
0-057 
2 - 20 
Seawater taken from Panama Bay contained 3 per cent, of 
sodium chloride, a sample from Simon Bay (Atlantic) contained y \7 
per cent., so that it will be seen from the foregoing table that some 
Anophelines, under stress of circumstances, may breed in very brackish 
water. 
EXPERIMENTS WITH LARVACIDES 
A number of experiments were carried out for the purpose of 
obtaining a cheap and efficient preparation for destroying mosquito 
larvae. Crude petroleum oil was frequently too viscid to nave a 
spreading power of the highest efficiency. When mixed wit cru 
carbolic acid, however, its spreading powers were incieased. 
Much of the crude carbolic acid supplied had been found upon 
analysis to consist chiefly of inert neutral oils with a small proportio 
5 per cent, to 10 per cent., of tar acids, and as this crude aci • 
used extensively as a disinfectant, experiments were conducte 
purpose of utilising if possible this crude carbolic acid as a ism ec 
and larvacide. It was found that crude carbolic acid, having a speci 
gravity not greater than 0‘96 or 097 and containing about 20 per 
of phenols or tar acids, when made into a soap vAth comm 
and an alkali yielded a product which was an ideal larvacide, having 
