45 



4. Rate: .01 gm. KCN per cu. ft. of space (see footnote page 

 41). Time of exposure, 30 minutes, daylight. Plant treated : To- 

 mato. Results : Extreme tips of some of larger leaves showed in- 

 jury ; growing tips of stems and the tenderest leaves uninjured ; all 

 adults killed, many being left suspended to the under surface of the 

 leaves by their rostral seta; and tarsal claws ^ none ever showed signs 

 of life after box was opened. 



5. Rate : .01 gm. KCN per cu. ft. of space. Time of expo- 

 sure, 30 minutes, cloudy day. Plant treated : Tomato nearly dead 

 from the effects of the insects' attacks, and a sprig of Eupatorium 

 infested with plant lice. Results : After a few days the young and 

 tender leaves of the plant appeared injured, [perhaps due to the 

 fumigation ; all adults killed ; eggs, larvae and pupae apparently un- 

 affected. Plant lice stupified, but recovered during the day after the 

 fumigation. 



6. Rate : .007 gm. KCN per cu. ft. of space. Time of expo- 

 sure, 30 minutes, after sunset. Plants treated : Tomato and cucum- 

 ber. Results : Plants not injured in the least, the cucumber plant 

 being in full bloom two days later ; many of the adult Aleyrodes 

 continued to show signs of life during the next day, but 36 hours 

 later all were dead ; eggs, larvae and pupae unaffected. 



7. Rate : .01 gm. KCN per cu. ft. of space. Time of expo- 

 sure, 25 minutes, cloudy day. Plants treated : Tomato and cucum- 

 ber used in experiment 6 and another tomato plant never before 

 treated. Results : Plants uninjured, even blossoms and flower buds 

 of cucumber escaping; all adults killed; eggs, larvae and pupae un- 

 affected. 



8. Rate: .01 gm. KCN per cu. ft. of space. Time of expo- 

 sure, 20 minutes, cloudy day. Plants treated: Tomato and cucum- 

 ber used in experiments 6 and 7, and a cucumber plant never before 

 treated. Results : One leaf of tomato slightly injured, plants other- 

 wise unaffected ; all adults killed ; eggs, larvae and pupae unaffected. 



9. Rate : .01 gm. KCN per cu. ft. of space. Time of expo- 

 sure, 20 minutes, after sunset. Plants treated; Tomato, badly in- 

 fested with Aleyrodes and red spider, and sprig of Eupatorium in- 

 fested with plant lice and Aleyrodes. Results: Plants uninjured ; 

 all adult Aleyrodes killed; red spicier unaffected; plant lice all stupi- 



