THE NATURAL HISTORY OF BOMBAY MALARIA. 417 



Tadpoles and frogs do not appear to be of the least value in 

 keeping a place free from mosquito larvae, and the latter are dis- 

 tinctly harmful, as they prej?" upon small fish which might other- 

 wise serve this purpose. Turtle are useless for destroying mosquito 

 larvae and gold fish are not always efficient, numerous anopheles 

 laiwae often being- found in the same tank or fountain with them. 

 A small fish, known locally as " Piku" is far more useful ; but it 

 must be present in sufficient numbers, and its efforts must not be 

 hampered by floating weed or rubbish. 



During the past few months this fish has been introduced ex- 

 perimentally into 15 wells which contained large numbers of larvae 

 of N. stephensi. All but two wells were rapidly cleared of mos- 

 quito larvae and in the latter they had been reduced in number, 

 but the presence of floating matter, leaves and flowers, afforded 

 a safe cover for a few mosquito larvae which thus escaped des- 

 truction. 



The " Piku'" fish which has been identified for me by Mr. Kin- 

 near as Haplochilus Uneatus were first, I believe, experimented with 

 by the late Mr. E. H. Aitken who called them " Scooties" be- 

 cause of the way in which the}^ darted about in the water. They 

 are quite small fish rarely reaching 3 inches in length. When 

 young they possess a brilliant white spot on the top of their heads 

 just between the eyes. This spot is less noticeable in the older 

 fish which become more striped about the body. Captain Liston 

 showed me these fish when first I came to Bombay. They can 

 be caught in considerable numbers in the stream which flows from 

 the Vehar Reservoir past Marol and Kurla. 



Since experimenting with " Piku " fish or il Scooties " I have 

 come across two other species of fish which destroy mosquito larvae. 

 One of these fish can be obtained from ponds and tanks at Thana 

 and is known locally as " Kazari " or " Kasara. " Mr. Kinnear has 

 indentified it for me as Anabas scandens. 



The specimens of the fish which I have seen have been small, 



: varying in size from 2\ to 6 inches, but I am told that it often 



j reaches a length of 12 inches or more. Some of the fish are blackish 



in colour but many of them have a reddish tint on the back above 



the gills. They are rather thick-set in shape with big heads and 



