266 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XV. 



A word as to the method I have found most successful for collecting 

 the larvae. Select a tank of any size, near a native village, which has 

 floating on its surface a collection of water weed, but not sufficient to 

 form a scum over the entire surface. Take a peg tumbler and skim the 

 surface of the water, preferably in clear water near the margin between 

 the masses of weed ; do not skim too rapidly, or the contents of the 

 tumbler will be washed out as rapidly as they are taken in, or 

 too slowly, otherwise the larvae will have time to dive to the bottom ; 

 but with a happy medium begotten of experience. A strange collection 

 of the denizens of the pond will be found in the tumbler, but after 

 allowing the contents to settle, the Anopheles larva? will come 

 to the surface and can then be transferred to another vessel — a French 

 plum jar does admirably. Where the larva? are abundant, a hundred 

 specimens or more can be collected in an houv. It is quite immaterial 

 whether the tank is full of frogs or not : one can frequently obtain a 

 haul of larva? in their immediate proximity. It would be wearisome to 

 recount my manifold difficulties in bringing my larva? to maturity, and 

 it is to enable others to avoid my numerous pitfalls that I write 

 these notes. 



The larva? require constant sunshine, plenty of water weed and a 

 vesssel with a broad surface. I lost numbers by keeping them in a 

 French plum jar in the shade ; now I expose them to the full sunlight 

 all day. A glass finger bowl does admirably, and being placed in the 

 sunlight causes the food plant to grow. It is not necessary to cover 

 the bowls with muslin, but they should be examined most carefully 

 every evening, and any larva? turned to pupae should be at once 

 transferred to glass test tubes with a teaspoonful or so of water and 

 carefully stoppered with cotton wool. It is important that all bowls 

 and test tubes should be labelled with the place and date of capture. 



By varying the amount of sunlight and the temperature of the 

 water the growth of the larva? can be materially hastened or delayed. 

 It is advisable to remove from the bowls any other water creatures,, 

 such as the larvse of dragon flies, water beetles, " water boatmen," etc., 

 which no doubt feed extensively on Anopheles. 



The staple food of the larva? is no doubt the green alga? floating 

 on the water, but it is not by any means their only food. I have seen 

 them eating pieces of Nais graminea and have kept and reared 

 larva? on a minimum of vegetable diet, their chief sustenance being 

 derived from the decaying bodies of insects such as butterflies, cock- 



