334 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



pluvialis) on the wet foliage. The caterpillars exhibited a most decided 

 aversion to the sprayed foliage, crawling about, collecting in masses 

 and suspending themselves on elongated web ropes and dropping off. 

 By noon, fully 60 per cent were apparently dead, though none had fed. 

 These died in a balled up heap in the center of the mass of foliage. 

 The few remaining caterpillars were restless, sick and writhing about. 

 Observations at 5.00 p. m. showed about all dead; some which had 

 dropped apparently dead, showed signs of life, but were very sick. 

 The next morning, April 10, all were dead or had left. A fair per cent 

 of those which dropped had recovered and crawled away. One small 

 incision in the margin of a leaf was observed, but there were no other 

 apparent signs of feeding. 



Experiment B. 



April 13, 1916. 8.45 p. m. 

 Sprayed foliage of apple as follows: 

 No. 1, Pratt's Nicotine 40 1-800 

 No. 2, Black Leaf 40 1-1200 



Applied as fine misty spray thoroughly saturating foliage. Placed 

 on table to dry. April 14, 9.00 a. m., placed approximately 300 small 

 caterpillars on each No. 1 and No. 2. Foliage perfectly dry. 



The caterpillars showed a decided aversion, were restless, crawled 

 about, formed long web ropes and dropped off. Often one would be 

 observed to rear the head and half of the body from the foliage, writhe 

 about and spew up drops of dark liquid as grasshoppers do, apparently 

 very sick. At 3.00 p. m., 50 per cent were apparently dead, the others 

 very sick. Many which had dropped and lay curled in grotesque 

 positions as though having died in great pain, eventually recovered 

 (after 3 hours or more) and crawled away. The following day, April 

 15, a few were observed to have fed on both Nos. 1 and 2. Where 

 they had fed, they were apparently in all cases really dead. One fact 

 stood out particularly, of the many which had dropped, apparently 

 dead, without having fed, they had almost without exception, recov- 

 ered and crawled away. The drop on No. 2 was a little heavier than 

 on No. 1, with a little more feeding indicated on No. 1. The cater- 

 pillars were about all dead or had crawled away the next day, April 16, 

 from both Nos. 1 and 2. To see if the action of the material was still 

 effective, 75 fresh caterpillars were placed on No. 2. The action of 

 the caterpillars was the same as that of earlier forms, restless, sick and 

 dropping off. This would indicate that the action, whatever it is, 

 extends over a period of three days at least. 



