30 GNATS Oil MOSQUITOES — CHAPTER II 



history of the genus Culex can be followed out with great 

 ease, but this is by no means equally the case with 

 Anopheles, the species of which are very difficult to main- 

 tain in captivity, and I have not yet succeeded in rearing 

 any batch from egg to imago. Very often the females 

 refuse to deposit their eggs, or when they do so the larvae 

 rapidly die, and the experiences of numerous correspondents 

 have been similar. It is difficult to say why this is so, as I 

 have used vessels holding much more water than many 

 natural collections I have met with containing Anopheles' 

 larvae, have had them partly filled with mud from genuine 

 Anopheles' pools, and tried in every way to as nearly as 

 possible imitate natural conditions. At any rate, it is 

 useless to attempt to experiment in test tubes and such-like 

 small receptacles, and I am inclined to think that the best 

 plan will be to have made a frame of wire gauze large 

 enough to cover a natural pool. In the north-western 

 provinces of India, at least, the scale of such an experiment 

 need be neither unwieldy nor costly, as here, perhaps, the 

 commonest natural haunt of Anopheles' larvae are certain 

 small masonry tanks, one or more of which are to be found 

 in the garden of almost every bungalow, and these are often 

 no more than two or three feet square. 



For rearing perfect insects from a comparatively limited 

 number of larvae taken from some natural source, a very 

 handy little apparatus may be improvised from one of the 

 ordinary prune bottles fitted with a screwed metal top. 

 The greater part of the middle of the cap is cut out, taking 

 care to leave at one point of the circumference a tongue-like 

 projection to serve as a support for food. A single loop of 

 wire is soldered on to the sides of the cap, of sufficient 

 height to serve as a support for the bag of gauze or " leno," 

 which when bound with string to the rim of the cap 

 completes the apparatus. All appliances for observing 

 captive Anopheles should be well fitted, as they will discover 

 and creep through the smallest interstice, and much of the 

 ordinary Mosquito netting sold is quite valueless as a pro- 

 tection against them. 



The study of the habitual resting position of living 



