-74- 
The Ne'" T Jersey Agricultural Experiment Station ( 212 ) in 1938 stated 
that in studies on pea aphid control derris dusts destroyed a large 
number of syrphid fly larvae, '•'hich predator /enemies of the oea aphid* " 
/ are 
Tabenidae 
The United States Department of Commerce, ^ureau of Foreign and 
Domestic Commerce ( 300 ) in 1938 published information received from 
the American Consulate General at Frankf ort-on-Main, Germany, that 
rotenone-containing preparations had been found to be most effective 
in Germany for combating the horsefly pest. 
T ipul i dae 
Tipula spp. 
Thompson ( 273 ) in 1928 tried derris in poison bait against leetherjacke" 
in South Wales and found that, although it did 'not give as good results as 
the peris green bait (l lb. peris green, 20 lb. bran, moistened w ith 1/2 
imp. gal. m ater) , it is obviously of definite insecticidal value when used 
in this way. On the derris-treated plot numerous earthworms, and also some 
slugs, were found lying dead on the surface. Derris powder clearly does 
not render the bait distasteful to the pests named, as appeared to be the 
case with sodium fluosilicate. The derris bait was composed of 10 pounds 
of bran and half a rjound of derris ponder distributed over half an acre 
of oats. Thompson concluded that derris ponder gives moderately good 
results. 
An anonymous (6_) writer in 193? stated that derris was ineffective 
against craneflies. 
Trypetidae 
Cera titis ca-piteta (Wied)., the Mediterranean fruitfly 
Mille-r and McBride (205) in 1931 recorded tests of various materials 
used in a solution of 50 rounds of sugar, 10 gallons of sirup, and 190 
gallons of ^eter, against the Mediterranean fruitfly in Florida. he 
sirup was a very chear> grade of black- stray) molasses, and the sugar was 
a coarse brown grade. The addition of 1 pint of a proprietarv product 
called "Derris Emulsion 5 percent derris resin" to 200 gallons of this 
sugar solution caused a mortality of 80 percent of the flies in 9 days, 
as compared with a 12-percent mortality in the check test. 
Bawft£4ier and Foury (36) in 1936 reported that molasses plus derris 
(14kg. of molasses, 1 liter of commercial insecticide containing 50 
. of rotenone, and 100 liters of water) killed 50 percent in 7 days. 
Arsenicals and fluorine compounds t^evc much better results. 
Rothe ( 244 ) in 1937, in discussing means of combating this species 
