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Chaoborus astictopus D. & S., the Clear Lake gnat 
Derris powder (5 percent of rotenone), tested as a larvicide 
against this nonbiting midge, was less effective than pyrethrum.-- 
Deonier and Lindquist ( 1 40 ) . 
Culex pipiens L., the northern house mosquito 
In a glass chamber derris dust was more effective than pyre- 
thrum powder.— Mir onov and coworkers ( 420 ) ♦ 
Culex quinquefasciatu3 Say, the southern house mosquito 
Ground derris root was toxic to all instars of the larvae. The 
minimum concentration necessary for 100 percent mortality rose with 
each succeeding instar, and the concentration necessary to kill the 
early third instar in 48 hours was 0.01 gm. per 1000 cc. When no 
food material was available the minimum concentration necessary for 
100 percent mortality was lowered, as was also the time taken for 
this mortality. — Pasfield and Woodhill (458 ) . 
Unidentified mosquito larvae 
An extract of the fruit of the Amur cork tree ( Phellodendron sp.) 
was more toxic to mosquito larvae than was a derris extract' (5.2 per- 
cent of rotenone) .—Ha Her (250) . 
Thanite was reported to be an effective substitute for pyre- 
thrum or rotenone in household sprays against mosquitoes, cockroaches, 
and other pests.— [Hercules Powder Company] (277 ) . 
Acetone extracts of the seeds of Tephrosia vogelii were lethal 
to both anopheline and culicine larvae in India up to 1 in 2,000. 
This action was due to deguelin, an isomer of rotenone.— Mans on (393). 
Xanthone was more toxic than rotenone to mosquito larvae, hav- 
ing been effective at a concentration of 1:1,000,000.— U. S. Bureau 
of Entomology and Plant Quarantine (524, p. 53) • 
Gasterophilidae 
Gasterophilus haemorrhoidalis (L.), the nose botfly 
Gasterophilus intestinalis (Deg.) , the horse botfly 
Gasterophilus nasalis (L«), the throat botfly 
Derris powder and rotenone crystals were given with feed to 
