- 24 - 
and v/hile they v/ere on the v;ing. Such flies became restless almost 
immediately and commenced cleaning themselves vigorously. Most flies 
so treated were dee-d within 24 hours, and as far as could "be ascertained 
all v/ero dead within 48 hours. 
Derris was also dusted on house flies "but in this case the pction 
v/as much slower and after one day none wore dead, and it v;as thought 
the material was not effective. These flics were not kept under observa- 
tion afterwards hut later v/orlc with derris led Zclsall and associates to 
thiixlc that had they "been kept under observation longer, a subsequent 
mortality might have been noted. 
Derris spray was also observed to kill several other flies of 
undetermined species, and was also observed to kill certo.in noctuid moths. 
Against the carrot rust fly, P sila rosae F. derris, in either 
dust or liquid form, gave a considerable measure of control, the material 
being applied to the soil surface about the time egg laying was in progress, 
the control being apparently also accompanied by a plant stimulation. 
A trunk of woolen goods sv/arming with adult clothes moths ^^ras given 
a libcro,l application of a 50-50 dcrris-hydratcd lime mixture. Tour 
days later all moths were dead. The trunk was examined a month later and 
no living larvae and no moths were found. 
A number of bedbugs, Clmex lectularius L. , vjctq confined in a vial 
with derris dust. They were active for 2 hours, but were all dead after 
5 1/2 hours. 
Derris spray, 2 pounds to 100 imperial go.llons of v;atcr, was in- 
effective against budworms (mostly Spilonota ocellana D. and S.), The 
fall v/ebv;orm, Hyphantria cunca Drury, is quite strongly resistant to 
derris dust and derris spray (lO lbs. to 100 gals.). Against the green 
apple aphid. Aphis pomi DeG. , derris, 5 pounds in 100 gallons without 
soap, gave practically complete control, being a little superior to 1 
pound of nicotine sulphate (40 percent). IJith the addition of a little 
soap to the solution, derris as lov/ as 2-l/2 pounds to 100 gallons of 
water gave 100 percent mortality, and is superior to 1 pound of nicotine 
sulphate (4t> percent). 
A dust conta.ining as high as 20 percent of derris plus 80 percent 
of hydrated lime proved ineffective against the green apple aphid v/hen 
applied to dry foliage. Derris dust requires moisture to malce its toxic 
properties effective against this aphis. 
In the inscctary, tests v/crc made against the potato aphid, 
Macros iphum solanifolii Ashm. The presence of moisture had a marked effect 
in increasing the toxicity of derris, for derris as lov/ as 2.5 percent in 
dust gave complete control. Derris in spray form required 5 pounds per 
100 gallons of water to produce 100 percent mortality, v;hilc nicotine sul- 
phate (40 percent), 1/2 pint to 100 gallons, gave the same control. In all 
cases it v;as found that derris v;as much slov/cr in action than the nicotine. 
