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chlorinated hydrocarbon insecticides. The methoxychlor caused complete 
knockdown in 5 minutes, DDT in 8, TDE in 17, chlordane in 53, and toxaphene 
in 73 minutes in tests made 24 hours after the cages had "been dipped. After 
2 months' exposure the methoxychlor, DDT, TDE, toxaphene, and chlordane 
caused complete knockdown of flies in 12, 62, 152, 248, and 3&0 to 720 
minutes, respectively. The cage treated with methoxychlor apparently lost 
little of its effectiveness. The knockdown of flies exposed to animals 
treated with the insecticides was the same as that determined in the 
laboratory, except that a longer time was required.— Eddy and Graham ( 127 ) . 
Chlordane has "been tested on animals exposed to horn flies in cages, 
and in field tests on dairy animals in Texas and "beef animals in Kansas. 
Wettable powder sprays at concentrations of 0.25 and 0.5 percent chlordane 
(applying an average of approximately 2 quarts per nature animal) have 
given good control of horn flies. The two concentrations protected animals 
for about 3 and 4 weeks, respectively. Chlordane was slightly inferior to 
DDT for the control of horn flies.-— Bishopp and Knipling (.24); Cuff (£2); 
Laake (280.); Smith (421); U. S. Bur. Ent. and Plant Quar. (46.8) . 
In Illinois chlordane emulsion was as effective as DDT and TDE (DDD) 
emulsions in controlling these flies on milk cows. — Bruce and Decker (56^) . 
Stomoxvs , calcitrans (L»), the stable fly 
The speed of knockdown and kill and the duration of effectiveness of 
11 of the more recently developed organic insecticides were studied in 
laboratory tests against the stable fly. Two 14-mesh copper-wire cages 
were dipped in a 1 percent solution of each test material in acetone. One 
cage was held indoors while its duplicate was stored outdoors, fully ex- 
posed to the effects of the weather. In the tests made 24 hours after the 
cages were treated, DDT and methoxychlor proved to be the fastest acting 
compounds and toxaphene and chlordane the slowest acting. From the stand- 
point of knockdown and duration of effectiveness, methoxychlor and the 
bromine analog of DDT appeared to be superior to any of nine other com- 
pounds tested, including DDT. Parathion, aldrin, and toxaphene appeared to 
retain their toxic properties longer than did TDE, gamma-BHC (95$), com- 
pound 153, heptachlor, or chlordane. — Eddy and McGregor ( 128 ). 
Chlordane, as a 2-percent water suspension made from a 50-percent wet- 
table powder, proved equal to DDT in the control of house flies and stable 
flies. — Muma and Hixson (33^). 
Same as for Sl phona irritans . — Bruce and Decker (56). 
Psychodidae 
Psychoda alternata Say, the filter fly 
In June 1949 filter flies, which had become tolerant to DDT, proved 
susceptible to chlordane. However, the third and fourth chlordane treat- 
ments were considered failures. This served again to illustrate the rapid 
acquisition of insecticide tolerance by insects through the treatment of 
the larval habitat, the filter bed. —Bruce (i£) . 
