REPORT ON MOSQUITOES. 73 



diameter, with a shallow cheese-cloth bag, and a medicine 

 dropper of extra large size. 



Every pool and every body of water, no matter how large or 

 how small, whether clean or foul, whether in the dense woods or 

 in the open meadow, should be tested with the glass. Even the 

 springs from which he drinks should be dipped at the edges. 

 The glass is used to make a preliminary test ; a c|uick dip, or the 

 draining of a grassy edge, will usually give at least a "show," 

 if anything is present. If it does not at the first trial, several dips 

 should be made until it seems reasonably certain that no larvae 

 are present. After a dip the glass should be held up to the light 

 and any larvae present will be detected in a few minutes, whether 

 floating like Anopheles or submerged like Ciilex. If larvae are 

 present the net comes into service. This should be swept just 

 beneath the surface, especially close to the edges, and as the water 

 drains out the larvae and pupae are left scjuirming and wriggling 

 in the sag, which may run to a little point. Turn this sag into 

 one of the bottles and pour a little water through to wash the 

 larva; into it. But not only the surface must be collected over; 

 some larvae live habitually close to the bottom, just over or even 

 in the layer of leaves and vegetable matter there to be found. To 

 obtain these, patience is necessary, and the net must be used so 

 as to take in some of the bottom material. Then holding the 

 net so that it remains half filled with water, gradually remove 

 all the debris and wash away the finest mud, leaving at last a 

 liquid sufficiently clean to find the specimens, if any. 



Some collectors use only a dipping glass, and from this the 

 larvae may be readily tubed out by means of the medicine dropper. 

 Always put some of the water in which the larvae were collected 

 into the collecting bottles, and never attempt to transfer to clean 

 water wrigglers taken in pools rich in organic matter. It is well 

 to try to separate the larvae according to their kind, as nearly as 

 may be, in comparatively small breeding jars, that the resulting 

 adults may be more certainly identified with the proper wriggler. 

 Where it is of great importance, pupae may be removed to small 

 bottles as fast as formed, the cast larval skin being put into 

 alcohol and the vial attached to the bottle containing the pupa. 

 In this way the resulting adult may be positively connected with 

 the early stag-es. 



Four ounce, wide-mouth bottles aire very convenient for breed- 

 ing small numbers of specimens, and one or two ounce bottles 

 answer for individual pupae. All transfers should be made with 

 a medicine dropper and the less the specimens are interfered with 

 the better they will develop. 



