'24 GNATS OR MOSQUITOES — CHAPTER II 



to escape. When the insect has been taken by the net 

 the bottle is passed into it, and it is easy to shp the bottle 

 over it as it sits on the gauze. The Mosquito should never 

 be left in the bottle for more than 90 seconds or it will get 

 too stiff to be conveniently set, and it should be pinned 

 immediately. 



Another very effectual killing agent is tobacco smoke, 

 which may be applied by holding a lighted cigarette a few 

 inches beneath the net and letting the stream of smoke play 

 over the entangled insect — or by puffing smoke from the 

 lips into the pill box or bottle, if it has been caught in that 

 way. 



Chloroform is useless for the purpose, as the insects 

 recover after setting, but a scrap of blotting paper moistened 

 with dilute hydrocyanic acid and slipped into the pill box 

 or bottle answers very well. 



Practically speaking, the only satisfactory method of 

 preserving Mosquitoes for identification is to pin them in 

 the method described below. 



It is of course very easy to mount Mosquitoes as micro- 

 scopic specimens in balsam, or to preserve them in bottles 

 inspirit, but such specimens are absolutely useless for iden- 

 tification, as their coloration depends entirely on the re- 

 flection of light from the scales with which they are 

 clothed, and is lost if they be immersed in balsam or any 

 other fluid ; and on this account, although additional 

 specimens preserved in spirit are not without their uses, 

 carefully pinned specimens are the first essential. The 

 following requisites are required for the work. 



^ (1) No. 20 Insect pins : (Obtainable from D. F. Tayler 

 and Co., New Hall Works, Birmingham). A quarter of an 

 ounce, costing about half a crown, will last a long time. 



' To avoid the difficulty of seeing the point of the pin, with the disc already 

 on it, Dr. Adolf-Eysell, in the Archiv. fiir Schiffs-und Tropen-Hygienc, Nov., 

 1900, p. 354, recommends the use of pins pointed at both ends. Such pins 

 would have the additional advantage of enabling one to remove the insect 

 from the disc to examine the ventral surface ; but, if adopted, it would be 

 necessary to first puncture the disc ; as the pin would certainly bend if forced 

 through the disc when held above the mosquito. 



