EXPERIMENTS WITH INSECTICIDES UPON POTATOES. 187 



After 6 hours a few of the slugs had left the treated plant and 

 crossed over to undusted ones, and in so doing were obliged to 

 climb over a piece of pasteboard 6 inches high which separated 

 the undusted from the dusted plants. On the ground under the 

 dusted plant were observed 3 dead slugs. 



After 22 hours a few more were found dead under the dusted 

 plant. More than half of the slugs had been driven from the 

 plants even forcing themselves out from under the netting. In 

 their eagerness to get away they left the plants which were free 

 from the Bug Death. Clinging to the leaves of the dusted plant 

 were a few slugs which on being touched fell to the ground. 

 Although apparently alive, they were dead. 



After 28 hours not much change was noticed, except a few 

 more driven and the remaining ones were apparently in a sort 

 of stupor. 



After 52 hours all the slugs were driven from 'the upper part 

 ' of stalks. A few were observed apparently feeding at the base of 

 the plants. 



After 68 hours about a third of the remaining few had crossed 

 over to the undusted plants. Those remaining on the treated 

 plant were eating heartily on the lower leaves, which had not 

 been reached in the dusting. No stupor was noticeable. 



The plants were allowed to remain several days after the sixth 

 observation, but nothing further of note was observed. 



SECOND EXPERIMENT. 



Statement of Conditions. In this experiment three plants were 

 also taken. One plant was dusted as well and evenly as possible 

 and then covered with the slugs. 



Results : The slugs almost immeditely and collectively sought 

 the underside of the treated leaves. 



After 6 hours several of the slugs were observed on the 

 undusted plants to get to which they must have, as in No. 1, 

 climbed over a strip of pasteboard 6 inches high separating the 

 dusted from the undusted plants. Five slugs had succumbed to 

 the Bug Death. 



After 22 hours nearly' three-fifths of the slugs had been driven 

 from the treated plant forcing themselves under the netting and 





