184 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
assumed that if there is do effect observable about one hour after ap- 
plication, the substance is innocuous. A general disturbance of the 
worms immediately follows the application of any substance, however 
harmless, and should not be taken in account. Effect through the 
stomach is not visible until after at least twenty : four hours, and in some 
instances not until the second or even the third day after application, 
as the worms (prompted no doubt by instinct) do not feed upon a sub- 
stance injurious to them until they get hungry. As to the third point, 
almost any strange substance thrown or sprayed on the leaves stops the 
worms from eating for a shorter or longer period, and observations as 
to the final result must, therefore, be extended over several days. A 
fourth point, viz., the possible influence of such applications on the ovipo- 
sition of the moth has already been referred to. 
The following list of plants experimented with is given without any 
systematic arrangement. If no effect on the worms was obtained by 
several independent experimenters, we have simply added "no result." 
Otherwise the results obtained by the individual observers are given in 
condensed form, with the name of the observer added in brackets. 
Ailanthus tree (" Tree of heaven," Ailanthus glandulosa). Decoc- 
tion and infusion of leaves. No result. 54 
Jamestown weed (Datura stramonium). Alcoholic extract from dried 
and ground seed. No result. [R. W. Jones.] Alcoholic extract and de- 
coction from leaves. No result. [E. A. Schwarz.] 
Bone set (Eupatorium perfoliatum). " Powdered leaves applied to the 
plant seemed obnoxious to the worms." [J. P. Stelle.] Infusion from 
leaves. No success. [E. A. Schwarz.]- 
Dog Fennel (Selenium tenuifolium and atitumnale). "This plant, of 
which I entertained considerable hopes, will render the cotton plant so 
obnoxious that the worms won't feed upon it, but it won't kill the 
worms." [J. P. Stelle.] Decoction, infusion, and alcoholic extract. 
No result. [E. W. Jones and E. A. Schwarz.] Flower heads dried and 
powdered. No result. [E. A. Schwarz.] 55 
Cocklebur (Xanthium strumarium). Alcoholic extract and decoc- 
tion. No result. [E. A. Schwarz.] 
Buckeye (JEsculus glabra). Alcoholic extract from fruits. No result. 
[R. W. Jones.] Alcoholic extract and decoction of leaves. No result. 
[E. A. Schwarz.] 
RAG weed (Ambrosia trifida). Decoction, infusion, and alcoholic ex- 
tract. No result. 
Hog Weed (Ambrosia artemisicefolia). Alcoholic extract and decoc- 
tion. No result. [E. A. Schwarz.] 
Indigo WEED(#cy;tma tinctoria). Alcoholic extract and decoction. 
No result. [E. A. Schwarz.] 
Deadly nightshade (Atropa belladonna). Decoction and alcoholic 
extract of leaves. No result. [E. A. Schwarz.] 
Tobacco (Meotiana tabacum). " Strong decoction of dry leaves freely 
