46 THOMAS L. BANCROFT. 



•be kept in ajar in the laboratory and are conveniently to hand 

 at any time; a pound weight of them will serve for numerous 

 experiments; they do not go rotten or even mouldy; and there is 

 no necessity, a3 with banana, to change for fresh every three or 

 four days ; a single date hung in the mosquito cage will serve 

 throughout the experiment however long it might last. Mosquitos 

 fed on dates live longer, and many species that will not live in 

 confinement more than three days on banana, e.g. Anopheles 

 musivus, Skuse, Culex vittiger, Skuse, thrive on dates and live for 

 upwards of a month. 



In studying the life histories of mosquitos it is often necessary 

 to induce them to oviposit in confinement. I have found that 

 when the water vessel in the cage contains putrid water mosquitos 

 will often oviposit, whereas they refuse to do so on clean water. 

 It is prudent however, to remove the eggs to cleaner water as the 

 larvae of many species cannot exist in putrid water. The water 

 may be rendered suitably putrid by the addition of a little fresh 

 cow-dung. 



In a number of experiments made with the object of ascertain- 

 ing whether certain very rare mosquitos [that would not live in 

 confinement in glass jars of the capacity of a gallon of water] 

 would live in larger cages and under more natural conditions; I 

 made a cage having a capacity of about a cubic yard in which 

 were placed several living plants in pots and large vessels of water 

 both fresh and salt, but the mosquitos lived no longer in it. It 

 seems therefore that nothing is gained by the use of such large 

 cages. 



