The Mosquitoes of New Jersey 175 



Borax. (Marked "refined," and furnished by Eimer and Amend.) 

 The resistance of 2 to 4-mm. C. pipiens larvae to borax in tap-water, 

 in amounts ranging from 3.5 to 20 gm. to 1,000 cc. was tested. In 

 the first six days the larvae seemed to be quite normal. The charge 

 was then increased so that the amounts ranged from 30 to 50 gm. 

 In two days more everything seemed normal. Two days later the 

 charge was in every case increased to 100 gm. In one day more 

 there were no changes. 



Copper sulfate. The resistance of 2 to 4-mm. larvae of C. pipiens 

 to copper sulfate in tap- water ranging from i to 20 gm. to 1,000 cc. 

 was tested. In one day all in 20 gm. were dead, and most of those 

 in 10 gm. had succumbed. In one day more all in 10 gm. and all in 

 5 gm. were dead. In one day more all in i gm. were dead. The 

 dosage for killing in 48 hours seems to be 5 gm. to 1,000 cc. 



Iron sulfate. (American Steel and Wire Co. product.) The resist- 

 ance of 2 to 5-mm. larvae of A. sollicitans to iron sulfate in tap- 

 water, with amounts ranging from 2.5 to 50 gm. per 1,000 cc, was 

 tested. Two days later all were dead in the 50-gm. solution, but all 

 in weaker strengths were alive. 



Pyrethrum. The resistance of C. pipiens larvae ranging from 3 

 to 6 mm. in length, by placing amounts ranging from i to 10 gm. 

 to 100 cc. of tap-water, was tested. The mixture was allowed to 

 stand over-night and 25 specimens placed in each jar the following 

 morning. In one day all were dead in the tested jars. The same 

 process was then repeated by using strengths ranging from i gm. 

 to 2,000 cc. down to I gm. to 10,000 cc. In two days all larvae were 

 dead. The test was then turned around, and jars in which the larvae 

 had been placed in tap-water were treated with a water extract of 

 pyrethrum at strengths ranging from 7 gm. to 3,000 cc. to i gm. to 

 20,000 cc. In I day all were dead in the i to 2,000 cc. solution; 

 in 2 days all were dead in the i to 3,000 ; in 3 days all were dead 

 in the i to 20,000 solution. 



Nicotine. The resistance of 5-mm. larvae of A. sollicitans to 40 

 per cent nicotine in tap-water at strengths ranging from i cc. to 

 1,000 cc. to I cc. to 40,000 cc, was tested. In one day all larvae 

 were killed in the i to 10,000 solution or greater. Also, the re- 

 sistance of 2 to 4-mm. larvae of C. pipiens to nicotine, in tap-water, 

 was tested, at strengths varying from i cc. to 30,000 cc. to i cc. to 

 60,000 cc. In 2 days all were dead in the i to 40,000 solution, and in 

 4 days all were dead in the i to 60,000. 



Quassia. A water extract of quassia was prepared by macerating 



