62 



brood and a portion of the frnit was found infested. While this is not 

 given as a good example of the effect of spraying, it seems strong enough 

 certainly to warrant the conclusion that the arsenite of ammonia will 

 prove as effectual as any other form of the poison against this pest. 



There were none of the Colorado Potato Beetles to be found in the 

 vicinity, so the poison could not be tested with them, a test that would 

 have been of course more satisfactory, especially with the larvae, because 

 of the fact that the dead insects can afterward be found readily around 

 the treated vines. 



I was able, however, to give a thorough trial of the insecticide prop- 

 erties of the substance later in the season on the common Handmaid 

 Moth (Datana ministra), which was very plentiful on some of the hickory 

 and black walnut trees in the vicinity. A single application of the 

 poison was found to kill the caterpillars in large numbers, evidently af- 

 fecting all that fed upon the leaves that had been reached by the poison. 

 Dead caterpillars began to be found in 24 hours from time of application, 

 and for two or three days afterward the caterpillars were dying off rap- 

 idly. The application was in this case made a little stronger than in the 

 first trials, and in a few clays the trees showed some injury from the ef- 

 fects of the arsenite, so it seems quite evident that the strength for these 

 trees must be kept within the limits indicated by the directions. The 

 liquid is very convenient to mix with water, and forms probably a very 

 uniform mixture, so that it seems to possess some points of superiority 

 ver the arsenites in solid form. 



