480 THE GYPSY MOTH. 



No. 5. July 27, 1893. A branch of oak was sprayed 

 with antinonnin, in the proportion of 3 Ibs. to 150 gal. of 

 water, and ten fifth-molt caterpillars placed upon it. This 

 experiment was started too late to be of any great value as a 

 test for the insecticide, as all the caterpillars pupated very 

 soon after the branch was sprayed, so that probably few if 

 any of them ate enough of the poisoned food to affect them. 



ARSENATE OF ZINC. 



Prepared in the same manner as arsenate of lead, by sub- 

 stituting a soluble zinc salt for the acetate of lead. 



No. 1. July 11, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of 1 Ibs. to 150 gal. 

 of water, and ten fifth-molt caterpillars placed upon it. 

 July 22, and again on the 25th, the branch was resprayed, 

 on account of heavy rains. Three of the caterpillars began 

 pupating, but none emerged. Foliage badly burned. 



No. 2. July 11, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of 1^ Ibs. to 150 gal. 

 of water, and five large and five small caterpillars placed 

 upon it. July 22, the branch was resprayed, on account of 

 rain. Six of the caterpillars pupated, four of which emerged ; 

 two of these, however, began to pupate before they had time 

 to eat much of the poisoned food. Foliage slightly burned. 



No. 3. July 10, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of 2 Ibs. to 150 gal. 

 of water, and ten large fifth-molt caterpillars placed upon it. 

 Six of these began pupating, but none emerged. Foliage 

 badly burned. 



No. 4. July 10, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of 3 Ibs. to 150 gal. 

 of water, and five large and five small caterpillars of the 

 fifth molt placed upon it. July 22, the branch was resprayed, 

 on account of rain. Five of the ten caterpillars began pu- 

 pating, but none emerged. Foliage badly burned. 



No. 5. July 10, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of 3 Ibs. to 150 gal. 

 of water, and ten very large fifth-molt caterpillars placed 

 upon it. July 20, they were transferred to a freshly sprayed 



