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EXPERIMENTS WITH PYRETHRUM. ao 
EXPERIMENT NO. 8. 
September 28, 10.50 a. m.—Seventeen full-grown larve of Datana 
ministra placed in a large breeding-cage open at top, and a small quan- 
tity of Cutlers’ No. 5 blown in through an insufflator, making an at- 
mosphere of dust. 
11 a. m.—Some half dozen are writhing uneasily. 
3 p. m.—Four are in convulsions. 
September 29, 10 a. m.—Two are practically dead, only a slight motion 
of the thoracic legs remaining; two more on their backs, and only mov. 
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. n.—No change. 
October 1, 9 a. m.—Five more dead. 
October 2, 9 a. m.—Six more dead. The others appear perfectly nor- 
mal. 
Nore.—This experiment possesses much interest when compared with 
experiment 7, as indicating the effects of the powder in a tightly-closed 
box and in an open cage, the latter approaching open-air conditions. 
EXPERIMENT NO. 9. 
September 29, 2.50 p.m.—A limb of hawthorn in the open air crowded 
with the Hawthorn Schizoneura (Schizoneura lanigera ?) 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. 
