The Collection of Larva 



The collection of larva. The collection of adult mosquitoes 

 should be supplemented by collecting the larvas, which may be kept 

 and bred out into adult mosquitoes. 



On account of the fact that pools and streams frequently 

 contain " anopheles " larvae when none can be seen on the surface 

 of the water, the method of " dipping " should always be employed 

 for their collection. 



One of the best things with which to dip for larvae is a large 

 tin mug, but a calico or muslin net with a long handle is of advan- 

 tage for fishing in the middle of a pool or stream. Besides the 

 dipper and net, a number of wide-mouthed bottles should be taken 

 when going out to search for larvse. When any collection of water 

 is reached, the dipper should be scooped along the surface, under 

 the grass or weed at the edge, and brought out full of water. If 

 any larvae have been caught they can easily be recognised in the 

 dipper when they rise to the surface, and they should then be 

 transferred with some of the water and weed into one of the wide- 

 mouthed bottles. In running streams care should be taken to dip 

 several times in the eddies and beneath the grass overhanging the 

 edge of the water, as in such places larvae are most likely to be found. 

 The larvae from different breeding places should be kept in separate 

 bottles, in order that when they have been bred out and identified, 

 the character of the breeding places of the different species will be 

 known. 



In searching for " anopheles " larvae, it is important to note 

 that no collection of water should be passed over without careful 

 examination, for it often happens that the most unlikely-looking 

 collection of water will yield many larvae. 



Each wide-mouthed bottle should be half-filled with water 

 from the pool or stream in which the larvas were taken. In some 

 cases, especially in the case of larvae collected from running 

 streams it is necessary to change the water daily if healthy larvae 

 are to be reared. The mouths of the bottles are covered with fine 

 muslin or mosquito netting, and allowed to stand in a warm place, 

 but bright sunlight should be avoided if possible. Each day the 

 adult mosquitoes which have developed from the larvae may be 

 transferred to a clean dry bottle, in which they should be allowed 

 to remain alive for one or two hours in order that they may attain 



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