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susceptible then houseflies. Dusting with a derris mixture containing 
0.5 percent of rotenone and 1.2 percent of ether extract killed all the 
flies within 24 hours.- 
Syrphida.e 
A llograpte obliqua Say 
Little ( 182 ) reported in 1931 that the larvae rrre not affected by the 
pondered root of Tephrosia virginiana in laboratory tests. 
^ampetia equestris J 1 ., the narcissus bulb fly 
According to a letter from Etablissements Rotenia to R. C. Roaricin 
1938, (Merodoja) Lempetie equestris on tulips was mitigated by a product 
containing 12 percent of powdered Lonchocamus nicou root (6 percent rotenone) 
and 88 percent of talcum. 
Schopp and Eide ( 247 ) in 1939 reported' the results of experiments with 
insecticides at Sumner, Wash., in 1938. Better than 50 percent control 
was obtained with a cube-root dust mixture containing 0.5 percent of 
rotenone. ^his dust mixture was applied at the base of the narcissus 
plant, where the bulb flies ordinarily oviposit. The first application of 
the insecticides were made on May 6, coinciding with the time of emergence 
of the first adults, and, since heavy showers occurred soon after the 
first applications, they '"ere repeated on May 23. 
Merodon geniculatus Strobl. 
in laboratory tests 
Delassus (70) in 1931 reported that/ steeping bulbs of ornamentals 
(Amaryllidaceae) in a decoction of derris was ineffective against larvae 
of this syrphid. 
Syrphus emericanus Wied. 
Little ( 182 ) in 1931 reported that the larvae were not effected by the 
powdered root of Tephrosja virginiena . 
S yrphus spp. 
Wilbaux ( 321 ) in 1934 tested extracts of 22-year-old leaves of Tephrosia 
vogelii and. reported that as a contact insecticide the leaves are about 
as toxic as nicotine. Larvae of Syrphus were resistant to sprays containing 
1 part -to 200 of the dry vegetable matter. 
Kelsall et al. ( 159 ) in 1926 reported that derris, 1.5 pounds per 100 
gallons of water, with soap, was used against aphids on a cutleef birch. 
Larvae of' syrphid flies ^ere killed and dropped in k : - few hours, but the 
aphids did not, appear to be affected during the first 12 hours. T'-o days 
later the tree was found to be completely free from aphids. 
Kuijper ( 163 ) in 1929 reported that syrphid flies were resistant to e 
spray containing an aqueous extract of derris root. 
