;;i ANNUAL REPORTS OF DEPARTMENT l OLTURE, 1051 
face, through action of lindane vapors, protected cloth From fabric 
for at least 6 months. Preliminary tests indicated that vapors 
from Lindane applied to the under side of a rug will penetrate the 
whole rug and destroy fabric pests in it. Studies showed that DDT 
and methoxychlor are among the most effective of the available in- 
:ides in preventing feeding damage by moths and carpet beetles 
to fabri< , 
Feathers treated with 0.85 percent by weight of DDT and agi 
months were still completely resistant to feeding damage by cl< 
moths or carpet beetles. A\ ool and hair felts were likcw ise proto I 
for the same period. The experiments to determini 
performed with funds authorized under the Research and 
Marketii g ."■■ 
Synthetic bristles made from casein, impregnated with 1 percei 
1 ) I >' I ' during manufacture, were found to be immune or high] 
1 1 arpet I eetles after aging for 1 v months. Untreated br 
heavily damaged. This work also was performed with funds 
authorized under the Research and Market Lng Act. 
Protection of Militar) Subsistence It<*ni> From Insecl Attack 
Iii\<*>ti«rat('(l 
Spi under way to develop m 
lour and other foodstuffs for the Armed Forces fro dam- 
1 oth and paper bags impregnated with various in- - and 
filled with flour are being tested under warehouse storage condit 
The flour is subject to nfestation by all the more important flour 
pests. Pyrethrum in combination with certain sts offers the 
most promise as a means for protecting the bagg< 
dama 
TOXICOLOGY OF INSECTICIDES 
Tin- problem of the potential hazards of new chemicals to man and 
animals continues of foremost importance in connection with the de- 
velopment of insecticides. The Bureau of Entomology and Plant 
Quarant inc. the Bureau of Animal [ndustry, and the 1 1 of 1 >airy 
I stry iiavi continued ;i cooperative investigation to determine the 
effects of the newer insecticides on livestock and the i \ U I to which 
remain a on or in animal and plant prod 
I e studie ing conducted in cooperation with the I 
ulnnal Experiment Station, with funds authorized under the 
. pch and Market ing Axt. 
Toxicity of Dieldrin to Livestock Determined 
Dieldrin ia among the most effective of the available insecticides 
for controlling pests of livestock and man. Special it itions 
undertaken to determine its toxicity i»> livestock. Sprays con- 
taining 0.1 percent <>1' dieldrin had no apparent toxic effects on 
calv( in l month old. When the concentration was increased 
6 <d 1 1 calves were killed. Lambs and pigs tolei 
concentration of 2 percent dieldrin sprays without apparent harm- 
ful effect . A ingle application of b jpraj containing l percent of 
