3i8 



Arthur I. Kendall 



K ^-O" 



absent at the bottom. For this reason holes are bored in the floor, 

 so that mosquitoes may be introduced and exposed at the point of 

 minimum efficiency of the fumigant. 



The cages are composed of wire netting of a mesh not less than 

 20 to the inch. This is extremely important; repeatedly the writer 

 has seen Stegomyia jasciata pass through a 17-18 mesh netting. 

 One end is closed with a circular piece of the same material, the 

 seam soldered, and the other end provided with a band of tin, one 

 inch wide, which fits inside the^cylinder, serving the twofold purpose 



of keeping the cylinder in shape at this 

 end and furnishing a point of attach- 

 "^ ment for the wooden stoppers. 

 I The latter are tapered so that they 



1 fit tightly inside the tin lining of the 

 ; wire cage, and at the same time fit 

 tightly into the hole in the side of the 

 box through which the wire cage just 

 passes. A half-inch hole through the 

 long axis of the wooden stopper per- 

 mits the introduction of mosquitoes, 

 and a cork stopper of appropriate size 

 closes this hole when the mosquitoes 

 TOP are in place, preventing loss of mos- 



FiG. 6.-T0P of box. quitoes or fumes. 



A collection of wooden stoppers which fit the holes in the sides 

 of the box, and which serve to close these openings when they are 

 ^ot occupied by mosquito cages, completes the outfit. 



The writer has not only tested comparatively the ordinary fumi- 

 gating agents, but has made a series of careful studies to show the 

 relation of results obtained under ideal conditions as initiated in the 

 apparatus above described with those obtained in large buildings. 

 The great amount of fumigating which is being done in Panama 

 permits such comparisons on a practical scale, and, without going 

 too much into detail, the results show in general that a slightly larger 

 amount of fumigating agent per unit space is required in the relatively 

 smaJl box than in a building which can be closed tightly. This 

 seems to be due, in part at least, to the proportionately large amount 



