364 JOURNAL OF ECOXOMIC ENTOMOLOGY [Vol. 14 



Lots numbers 1 to 4, 5 to 8, 9 to 12, aiid 13 to 16 inclusive were placed 

 together in screen cages. Lot niunber 7, consisting of syrup diluted 

 one part to five parts of water plus Black Leaf 40, one to 100, gave 

 the best results. No adults emerged successfully, 27 being killed be- 

 for completing the emergence and 15 pupae dead in the leaves. Lot 

 number 10, in which tobacco dust was added to the syrup gave good 

 results, 18 emerging successfully, 43 failing to emerge successfully, 

 and 21 entangled in the syrup. Lot number 13, consisting of soluble 

 pine tar plus Black Leaf 40 gave good results while the far used alone 

 did not show much promise. 



Later experiments with Black Leaf 40 ana Black leaf-resinate di- 

 luted 1 to 500 gave excellent control. The following table is typical 

 of the results seciured. 



Table No. II - Results Secured by Spraying Infested Twigs with Black 

 Leaf 40 and Black Leaf-resinate Diluted one part to 500 parts of Water 



Spray No. adolts No. adults fail- No. pupae Percent killed 



material emerging ing to emerge dead in the 



successfully si:ccessfully leaves 



Black Leaf 40 5 28 59 94..3 

 Black Leaf 



resinate 4 40 111 97.4 



Check 24 1 4 17.2 



A good kihing effect was obtained 4 and 5 days after spra^dng. Fig- 

 iu"e 4 shows the adults killed as they emerged after having sprayed the 

 leaves with Black Leaf 40 diluted 1 to 500. Unfortimately, the adults 

 emerged so rapidly that no time was available for testing Black Leaf 

 40 under field conditions. Soap added to the spray at the rate of 4 

 pounds to 50 gallons of water gave slightly better results by increas- 

 ing the wetting properties of the spray. The results secured in the 

 laboratory tests would indicate that the adults might be controlled 

 under field conditions by spraying at intervals of 4 or 5 days during the 

 emerging period. 



Spraying experiments with Black Leaf 40, pine tar dilutions, and 

 pyrethrum extract during the egg and larval stages gave only slight 

 control. 



Fumigation Experiments With Hydrocyanic Acid Gas and Car- 

 bon Bisulphide 



Laboratory experiments with hydrocyanic acid gas and carbon di- 

 sulphide gave results approximating those reported by Felt in the Jour- 

 nal of Economic Entomology for 1915. Young larvae in infested 



