22 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE. 
In 1880, Sayre (240) tested the effect of the flowers of Pyrethrum 
roseum on flies and tadpoles. Unger (282), in 1888, while exam- 
ining insect powders, made use of Kalbruner's "fly test. " He, how- 
ever, used a weighed amount of powder placed on a sheet of white 
paper, over which the insect was imprisoned with a glass. Tested 
against Blatta orientalis (Oriental cockroach or black beetle) and 
Acarus farinse in this manner, the powder from both the P. cinerarix- 
folium and the P. roseum killed the insects in about 45 minutes. 
About the same time, Goff (104), in America, made tests with P. 
cinerarixfolium grown in California and a powder prepared from the 
flowers of Pyrethrum roseum, grown in New York from seed received 
from the United States Department of Agriculture, to determine 
the relative time required to paralyze flies. These tests indicated 
that the powder made from P. roseum was slightly more effective. 
Hirschsohn (133), in 1890, while investigating the active constituent 
of insect powder, tested the activity of the powder by trying it on 
roaches. Two of the samples under investigation paralyzed roaches in 
3 minutes. From his tests on Blatta orientalis, Thorns (275) con- 
cluded that the physiological test was surer than either the micro- 
scopical or chemical test in arriving at an estimation of the worth 
of a powder. 
In 1895, Jelliffe (148) tested the action of insect powder on the 
common house fly (Musca domestica), the Croton bug or cockroach 
(Blatta germanica), the bedbug (Cimex lectutarius) , and some black 
beetles (species undetermined). 
Dowzard (71), in 1899, conducted some tests on cockroaches. 
Slaus-Kantschieder (261), in 1913, stated that although the micro- 
scopical and chemical methods of examination furnish a basis for the 
grading of insect powder, for the determination of the true value the 
physiological test must be made. He conducts the test as follows: 
A 25 cc. flask is taken, about 1 gram of insect powder added, the flask 
then closed and shaken well, after which the flies are introduced. If 
the powder is of good quality the flies will come to rest within one 
half minute and die within 5 minutes. If the flies survive this period 
the insect powder is to be considered as of low value and old. 
Kuraz (165) has recently tested a number of commercial samples of 
insect powder, as well as closed, half-closed, and open flowers, and 
Pyrethrum stems grown at Korneuburg, near Vienna, according to 
the method of Slaus-Kantschieder. The ordinary house fly (Musca 
domestica) was used in these tests, and the time noted in which the 
insect fell over on its back. The results are summarized in Table 2. 
