368 MOSQUITOES OF NORTH AMERICA 
country from imported dried flowerheads brought over in bulk. For this reason 
it was, many years ago, deemed very desirable to establish a pyrethrum-growing 
industry in the United States, and in 1881 the United States Entomological 
Commission imported and distributed the seeds of the two species above men- 
tioned to a number of correspondents in different parts of the country. The 
total success was inconsiderable. Further experiments another year met with 
comparative failure. About this time more extensive plantations were made in 
California and an insect powder was made by the Buhach Producing and Manu- 
facturing Company, of Stockton, California, which, being American grown and 
freshly ground, came into use, and is still being produced and sold under the 
proprietary name of “ buhach,” the word being supposedly derived from a Sla- 
vonic word “buha,” meaning flea. An article by the late D. W. Coquillett on 
the production and manufacture of this powder will be found in Bulletin No. 12, 
Division of Entomology, United States Department of Agriculture, 1886, pp. 
% to 16. 
Formerly most of the insect powders sold in the shops in this country had 
pyrethrum powder as a basis. It is now difficult to get a pure and thoroughly 
efficient powder. There is often adulteration. Frequently the powder made 
from the dried flowerheads is adulterated with powder made from the stems, or 
with other adulterants. Under the U. 8. Insecticide Act of 1910 it is now re- 
quired that the manufacturers of insect powders indicate on the label the com- 
position of the powder, unless made of the flowerheads of the following three 
species: 1. Chrysanthemum (Pyrethrum) cinerariefolium (Trev.) Boce.; 2. 
C. (P.) rosewm Web. & Mohr.; 3. Chrysanthemum marshall Aschers (syn- 
onym: Pyrethrum carneum M. B.). 
Pyrethrum powders are usually used dry and are puffed or blown into crevices 
frequented by insects, or puffed or blown into the air of a room in which there 
are mosquitoes or flies. The burning of the powder in a room at night is a 
common practice. The powder is heaped up in a little pyramid which is lighted 
at the top and burns slowly, giving off a dense and pungent smoke with an 
odor very much like that of the Chinese punk used to light firecrackers. Often 
the powder is moistened and moulded roughly into small cones, and after dry- 
ing it burns readily and perhaps with less waste than does the dry powder. 
Of late years in mosquito countries a number of mosquito pastilles have been 
sold, and many of these are moulded from powders that contain more or less 
pyrethrum. The efficacy of the burning pyrethrum in a close room is almost 
perfect. It will not actually kill all the mosquitoes, but will stupefy them and 
cause them to fall to the floor where they may be swept up and burned. With 
the windows open, however, and constant currents of fresh air blowing through 
the room, this fumigation is not especially effective, and it is necessary for pro- 
tection to sit in the cloud of smoke. 
The pungent odor of burning pyrethrum is not disagreeable to most people, 
but to some it is disagreeable, and with certain susceptible individuals it pro- 
duces headache. It is apparently possible, however, to volatilize the oil without 
producing the actual smoke. Mr, H. W. Henshaw informs us that a few years 
