EXPERIMENTS WITH PYBETHBUM. 23 



EXPEREM i >. 8. 



September 28, L0.50 a. m. — Seventeen full-grown larvae of Datana 

 ministra placed in a large breedii >pen at top, and a small quan- 



tity of Cutler-' No. 5 blown in through an insufflator, making an at- 

 mosphere of dust. 



11 a. m. — Some half dozen are writhing uneasily. 



3 p. in. — Four are in convulsions. 



September 29, 1<» a. m. — Two are practically dead, only a slight motion 

 of the thoracic legs remaining ; two more on their backs, and only mow 

 ing slightly. The rest are evidently somewhat affected, but retain their 

 normal position, and are capable of strong motion. 



3.30 p. m. — One dead: five others badly affected. 



September 30, 9 a. m. — No change. 



October 1. 9 a. m. — Five more dead. 



October 2, 9 a. m. — Six more dead. The others appear perfectly nor- 

 mal. 



Note. — This experiment posse much interest when compared with 



experiment 7. as indicating the effects of the powder in a tightly-e"; 

 box and in an open cage, the latter approaching open-air conditions. 



EXPERIMENT NO. 9. 



September 29. 2.30 p. m. — A limb of hawthorn in the open air crowded 

 with the Hawthorn Schizoneura [Schizoneura lanigera f puffed upon 

 copiously with Cutlers' No. 5, so that every individual must have had a 

 dose. 



October 1, 9.30 a. m. — Could see no effect whatever. The lice were 

 just as numerous and just as healthy. 



