486 THE GYPSY MOTH. 



the summer of 1894, to determine, if possible, whether the 

 gypsy moth caterpillars are able in any way to select their 

 food, and thus choose the non-poisoned leaves in preference 

 to leaves treated with arsenical poisons. For this purpose, 

 a definite number of caterpillars were confined upon leaves 

 treated with poisons applied in various ways, and the results 

 carefully noted for several days, or as long as there was a suf- 

 ficient amount of food for them to eat without being forced 

 to partake of either the poisoned or non-poisoned leaves. 



Experiment No. 1. Six elm leaves were selected, and 

 a series of bands and dots painted upon each, with Paris 

 green, in the proportion of 3 Ibs. to 150 gal. of water. 

 When the poison was sufficiently dry, so that it did not run 

 upon the surface of the leaves, each one was placed in a box 

 with three fourth-molt caterpillars. Sixty-five per cent, of 

 the feeding was upon the unpainted parts of the leaves and 

 thirty-five per cent, upon the painted parts. 



Experiment No. 2. A series of bands and dots was 

 painted upon six willow leaves, with Paris green, in the 

 proportion of 3 Ibs. to 150 gal. of water. After the poison 

 had been applied, each leaf was placed in a box with three 

 caterpillars of the fourth molt. These fed about equally 

 upon the painted and unpainted parts. 



Experiment No. 3. Six willow leaves were selected, 

 and a number of transverse bands painted upon each with 

 Paris green, in the proportion of 3 Ibs. to 150 gal. of water. 

 The bands were one-fourth of an inch wide, and the un- 

 painted space between them one-half of an inch in width. 

 Each leaf was then placed in a box with three fourth-molt 

 caterpillars. Sixty per cent, of the feeding was upon the 

 non-poisoned part of the leaves and forty per cent, upon 

 the poisoned parts. 



Experiment No. 4. A medium-sized twig on an apple 

 tree was selected, and from it were removed all the damaged 

 and a part of the perfect leaves, so that there were only 

 twenty-five leaves left upon the twig. On each of these 

 were painted three broad, transverse bands, with Paris 

 green and lime in water, in the proportion of 3 Ibs. of 

 Paris green and 5 Ibs. of lime to 150 gal. of water. Ten 



