426 THE GYPSY MOTH. 



molt, were placed on elm leaves which had been sprayed 

 with Paris green, in the proportion of 1 II). to 150 gal. of 

 water. One died the fourth day ; three died and one pu- 

 pated the sixth day ; two died the ninth, one the tenth, one 

 the eleventh and one the twelfth day. 



Check experiment : one died the second day ; two pupated 

 the sixth, one the seventh, one the ninth and one the tenth 

 day. 



No. 35 (field experiment). — July 7, 1894. Ten cater- 

 pillars, of the fifth molt, were placed on willow branches 

 which had been sprayed with Paris green, in the proportion 

 of 1 lb. to 150 gal, of water. Two pupated the fourteenth, 

 two the sixteenth and three the eighteenth day ; one died 

 the nineteenth and two pupated the twentieth day. 



No. 36 (field experiment). — June 26, 1893. A branch 

 of apple tree was sprayed with Paris green, in the propor- 

 tion of 1 lb. to 150 gal. of water, and ten fifth-molt cater- 

 pillars were placed upon it. Of these, six died before pu- 

 pating ; four pupated, three of which emerged. For some 

 reason the foliage appeared to be quite badly burned, 

 although the Paris green was in the proportion commonly 

 used for spraying. 



No. 37 (field experiment). — June 26, 1893. A branch 

 of apple tree was sprayed with Paris green, in the propor- 

 tion of 1 lb. to 150 gal. of water, and ten fifth-molt cater- 

 pillars placed upon it. In this experiment the poison took 

 efiect more quickly than in the corresponding experiments, 

 all of the caterpillars having died within three Aveeks. 



No. 38 (field experiment) .— July 12, 1893. A branch 

 of hop-hornbeam was sprayed with Paris green, in the pro- 

 portion of 1 lb. to 150 gal. of water, and ten caterpillars of 

 the fifth molt placed upon the branch. July 21, the foliage 

 was so badly burned that the caterpillars were transferred 

 to a freshly sprayed branch of oak, which was resprayed 

 July 27, on account of the rain. Four caterpillars pupated, 

 two of which emerged. Foliage of the hop-hornbeam very 

 badly burned ; that of the oak burned somewhat less. 



No. 39 (field experiment). — July 12, 1893. Paris green, 

 in the proportion of 1 lb. to 150 gal. of water, was allowed 



