1913] 



Determining the Flight of Mosquitos 



17 



buildings. The men selected for this work should be provided 

 with a killing-tube made of a heavy walled test tube, 6 inches 

 by IM inches, containing a four inch cotton plug saturated with 

 chloroform, over which are a few circular pieces of blotter paper. 

 The collector merely superimposes the mouth of his tube over 

 the mosquito he sees on the wall or clothing, the chloroform 

 vapor, readily generated by the aid of the heat of his palm, 

 quickly kills the insect. A few days' work will render the novice 

 an expert. All the mosquitos caught in one day in one building 

 should be placed by the collector into a circular pill box, of 

 which he should have a good supply. This box should be 

 labeled, giving the date, house, and the initials of collector. At 

 the close of day, these boxes should be turned over to the person 

 in charge, who should check them and rectify any existing 

 errors. The next step is to examine these captured mosquitos 

 for color. (See pp. 19-20). 



B. Collection by Traps: If the buildings are well-screened 

 and holes and crevices blocked, mosquito traps may be used to 

 excellent advantage. This is being done on the canal zone, 



Fig. 4. Mosquito /m/>, in section, s, inner "V" section; u, middle "V" sec- 

 tion; a, slits in the "V" sections; e, semicircular outer envelope; o, sill of build- 

 ing. The "V" sections are detachable. 



