54 r.ri.Li.nx L201, u. s. department of agriculture. 
Of the 260 species of plants catalogued, 94 were found by the 
writers and others to have little or no effect as insecticides, and 109 
other species are recorded by other writers as used for insecticide-, 
but without citation of experimental evidence. 
CONCLUSIONS. 
Of the 2G0 species of plants catalogued, only about 5 per cent 
furnish material for efficient insecticides, and of these only about 
half may be regarded as satisfactorily efficient. The latter include 
three species of Chrysanthem/wm (cmerariaefoUum, coccinewn, and 
marschaZUi) , used for making pyrethrum or insect powder; two 
species of Derris (eUiptica and uliginosa)^ and a Peruvian plant 
known locally as "cube." The extracts of these, combined with soap, 
proved to be promising contact insecticides and compete favorably 
with nicotine sulphate in efficiency and probably in cost. 
Relative to the other species catalogued, most of them are not 
worth further consideration. It does not seem at all probable that 
satisfactory insecticides can be obtained from the commoner weeds or 
flowers or from plants known to be only slightly poisonous to man 
or other animals: but with regard to the poisonous plants, particu- 
larly the fi<h-poisons. found in the Tropics or subtropics the chances 
to obtain other efficient insecticidal material are very promising. 
LITERATURE CITED. 
(1) Abbott, W. S. 
1920. Results of experiments with miscellaneous substances against 
chicken lice and the dog flea. U. S. Dept. Agr. Rul. 888, 15 p. 
(2) A MUM'. E. 
1904, Nouveaux procGdes de destruction de I'oidium el du puceron 
Lanigiere. I» Rev. Hort., 70 annee, t. 4, Paris, p. 83-84. 
(."») Anonymous. 
isc,:?. Anthemis cotula. /// Pharm. Ztschr. fiir Russland, )ahrg. 1, no. 
23, p. 578. 
(4) 
(5) 
1875. Ersatz des persischen Insektenpulvers. In Ztschr. Allg. Osterr. 
Apoth. Ver., 13 jahnr., no. 21, p. 346. 
1886. Ricinus communis as an insect powder. In Chemisl and Druggist, 
v. 29, Sept., j). 410. 
1892. Ensektenpulver. hi Pharm. Ztg., .".7 jahrg., no. 103, Dez., p. 798. 
1901. Catalogue of collections of pests and insecticides (Com. Agr. 
Parasit. Secy. Pub. Prom. Mexico, 1!><H. p. 6). In Exp. Sta. 
Record, V. 13, 1901 and 1902, p. 474. 
(6) 
(7) 
(8) 
1'.)17. Infusion <»f broom t<M>s as a larvicide. i» Pharm. Jour, and 
Pharmacist, v. <.)^ (4th ser., v. 44), no. 2783, p. 130. 
(ID Back, E. A., and RABAK, Frank. 
1922. Red cedar chests as protectors against moth damage. V. S. I>ept. 
Agr. Bui. 1051, 14 p. 
( mi Bebgey, l>. II. 
1!>1l\ The principles of hygiene. Philadelphia, p. 399. 
( n ) Bishop, Wm. D. 
1859. Government experimental and propagating garden. In Rpt. Comm. 
of Patents, Agr., p. 13, Washington, 1860. 
(12) Bohmer, K. 
1895. Oaber Chrysanthemum corymbosnm. In Pharm. VAu.-. jahrg. 40, 
- no. 84, Aug., p. 523. 
