18 Annals Entomological Society of America [Vol. VI, 



and the trap illustrated was developed by Mr. Chas. H. Bath, 

 sanitary inspector. Such or similar traps greatly add to the 

 data, and if placed to buildings that harbor a large number of 

 people asleep, will attract many mosquitos, save them, and in 

 regions of malaria, greatly reduce the number of such cases. 

 The traps should be numbered and recorded on charts where 

 their location with respect to the wind is seen at a glance. 



Traps should be taken down each morning, at about nine 

 o'clock was found best, and the adults in these killed and placed 

 into pill-boxes, one box for each trap, and each box properly 

 labeled. There is no apparent need for blocking up the open- 

 ing in the wall when the traps are removed. During five months 

 with these traps, the writer never found a single mosquito that 

 entered during the daytime. The method used was to place 

 a new trap in the place of the one taken out. 



A very satisfactory and quick way to kill the mosquitos in 

 the traps is to place the trap into a closed chamber and fumigate 

 with sulphur dioxide. The question arises whether or not this 

 gas combines with the moisture in the mosquito to form sul- 

 phurous acid (H2SO3), and whether or not this will bleach what 

 color is on the mosquitos. The data following, of a series of 

 tests made, indicate the negative is true : 



50 Culex sp. Stained lightly with eosin, left in SO2 chamber 

 for 3 hrs. ; no bleaching. 



100 Culex sp. Stained lightly with eosin; 100 Culex sp. 

 with gentian-violet, exposed 13 hrs.; no bleaching. 



30 Culex, 70 Anopheles albimanus et malefactor stained 

 lightly with methylene-blue, exposed to burning sulphur and 

 generated steam for 33^2 hrs. ; O. K. 



10 Culex sp. each slightly stained with all stains cited, 

 exposed 15 minutes; no bleaching. 



Paper and blotters, wetted and colored, exposed for 6 hrs.; 

 no bleaching; no acid reaction to litmus. 



Vials containing 1 : 10000 aqueous solutions of bismarck- 

 braun, methylene-blue, gentian-violet and eosin, exposed 3^2 

 hrs. ; no bleaching; no acid reaction. 



C. Collection in Tents. If patient and honest men are 

 procurable, army tents may be pitched at suitable places 

 radiating from the releasing point, and these men placed, one to 

 a tent, with a lantern, killing tube and boxes, to catch all 

 mosquitos that enter the tent. The lamp should burn dimly, 



