132 
bottles, as previously described (p. 91), and allowed to 
lay their eggs. 
If care is taken to place only one species in a 
bottle, the characters of the ovum may be noted, in 
addition to the adult insect. 
Some of the ova should be placed in fresh water, 
and an attempt made to determine the characters of 
the larva when it has hatched out and is sufficiently 
grown. 
2. Breeding out. —Full-grown larvae, and especi¬ 
ally nymphae, are collected. These are collected from 
every possible source. Scarcely any water in the 
tropics will be found free from some form of mosquito 
larvae. Even strongly brackish waters, containing 
over one per cent, of salt, often contain large numbers. 
Examine water from the following sources :— 
(i) Domestic utensils, cisterns, tins, pots, cala¬ 
bashes, boats, etc., in which there has been water for 
three or four days. The larvae of Stegomyia , Culex , 
etc., and only rarely Anophelines , will be found. 
(ii) Cess pits, pools full of decaying leaves, etc., 
sewage ditches. Note larvae of certain species of 
Culex , etc. 
(iii) Observe presence of the larvae of Stegomyia 
and Culex in the water which collects in the axils of 
banana leaves and other plants. Also, occasionally, 
Anophelines in large collections of water of this kind. 
(iv) Puddles of all kinds, with and without algae, 
ponds, tanks, swamps, rice fields, ditches, canals, 
rivers, streams, lake margins, and wells, and observe 
that in all, Anopheline , as well as Culicine larvae, may 
abound. 
Note that in waters covered with certain species 
of Lemna (duck-weed), Anophelines are rarely found. 
(v) Examine the larvae (p. 190) and roughly 
