12 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE 
states that “all insects having open mouth parts are particularly 
susceptible to this powerful drug.’’ Howard (138), in 1882, described 
the effect of Pyrethrum upon the heartbeat of Plusia brassicxe (cab- 
bage worm). 
A great amount of work has been done since 1879 by the United 
States Department of Agriculture and the various agricultural 
experiment stations in testing the efficacy of insect powder in destroy- 
ing or repelling harmful insects. A review of this work, however, is 
foreign to the purpose of this bulletin. Those interested may consult 
the following list of references to recorded tests given in the bibli- 
ography (p. 78): 2, 3, 9, 11, 26, 27, 28, 35, 36, 88, 44, 46, 49, 61, 52, 58, 
54, 65, 56, 61, 65, 66, 71, 72, 75, 87, 94, 96, 97, 98; OF, 100, TO pan20, 
125,128; 129, 138, 141, TIS LG, DOTS 16o AGT) tl Poe ee 
192, 193,195,200; 201, 208; 207 , 208-211 (217 218, Bat 2aeeae 
225, 226, 227, 298, 229, 230, 231, 232, 233, 241, 258, 262, 263, 264, 
270, 271, 272, 290, 291, 294, S2, S26. Other articles on the use of 
insect powder against different insects are listed in ‘‘ Bibliography of 
the More Important Contributions to American Economie Ento- 
mology,” published by the United States Department of Agriculture, 
Bureau of Entomology, Washington, 1890-1905, ‘‘ Index to the Liter- 
ature of American Economic Entomology,” published byethe Ameri- 
can Association of Ecohomic Entomologists, 1917, and ‘‘Le pyréthre 
insecticide de Dalmatie,”’ by Juillet (S20). 
A combination of pyrethrum and soap has proved a very effective 
insecticide (S6, S17, S21, S23). Kerosene extracts of pyre 
which are made by extracting the powdered flowers with kerosene or 
other light mineral oil in the proportion of 1 to 2 pounds to the 
gallon, have been extensively sold in the United States recently. 
Some investigators claim that the powder must be taken internally 
to be effective; others state that it kills by external contact. Many 
of the reported failures were no doubt due to the fact that a powder 
adulterated with powdered stems was used in the tests. 
At present insect powder is used largely against bedbugs, cock- 
roaches, ants, flies, mosquitoes, and other household insects, as well 
as plant lice and fleas on pet animals. 
Although insect powder is an efficient insecticide against many 
insects, the plant from which it is made is not tree from insect enemies. 
In 1884, Riley (225, p. 416) received specimens of Macrodactylus 
subspinosus, found on Pyrethrum plants in large numbers and 
apparently eating both leaves and flowers, and Chauliognathus mar- 
ginatus, not so numerous and apparently attracted chiefly by the 
flowers. He states that a number of insects feed on Pyrethrum. while 
it is growing. In 1890 he (229) again called attention to the fact that 
the Macrodactylus subspinosus, or rose chafer, devours the blossoms 
of the Pyrethrum cinerarizfolium. 
EFFECT OF INSECT POWDER ON ANIMALS 
Although insect powder is generally considered harmless to the 
higher animals, several cases where it has produced serious symp- 
toms are recorded. 
As early as 1858 Boucard (34) described the case of a woman, 
who had strewn much insect powder upon her bed, being taken with 
a headache, roaring in the ears, bloating of the face, pain in the 
stomach, nausea, sweating, and symptoms of syncope. About the 
