Bull. Ent. Research. Vol. VI. Part 1 



Plate III. 



Fig. 1. A potato field at Elmep, New Jersey; the plot to the right of the photograph has 

 been treated with Bordeaux mixture, and the plants are healthy and vigorous. 



Fig. 2. The same field, on the same day, showing a control plot treated with lead arsenate, 

 adjacent to that represented in the photograph above. Note the marked difference in 

 the foliage. 



