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saw-flj-, l-jFmatus ( pteronide a) ri"bessi Scop. , but Durham found that it had 
no effect as a contact poison on the black "bean aphid, A, nmici s L, , and 
the v/oolly aphid of the apple, Sriosom a lanigenmi Hausm. Trial on frogs' 
hearts showed that the vagus was paralysed, so that stimulation of the 
nerve failed to cause the norraal vagus inhibition. In England Durham 
fouiic that Culicid larvae, Theobaldia ann uIiitb Q , were killed in a l-in'-40,000 
suspension of the dried powdered crude root of D, elliptica, A solution 
of 1 in 10,000 killed the larvae in 29 hou.rs and the pupae in from 24 hours 
to 3 or 4 daj's. Another experiment with the larvae of Culex pipi3ns shov/ed 
that they died in less than 16 hours (pupae in less than 24 hours) v.'ith 
solutions of 1 in 1,000, 1 in 2,000 and i in 5,000 of the whole root; with 
1 in 10,000 the larvae were killed in 20 hours ond thtt pupae in 24 hours, 
A solution of 1 in 1,000 of the extract is enough to make the wato^r cloudy. 
The California Agricultural Zxpcrimont S'iation (15) in 1923 roportcd 
the results of spra;;'-ing and dusting tests with derris made by L, T, TThitc, 
under tlio direction of E, R, dc Ohg. A dust made from ground dorris root 
mixed with 60 percent of inert carrier v;as found to give perfect control 
of the biting lice Monopon biseriatum Piagct and G-oniocotcs ^Igas Tr.schcn- 
borg of the fowl; and of the cucking lice Gyropus oval is l!"it2sch and 
Gliricol r. y.orcclli L. of the guinea pig, 
Fryer, Stenton, Tattersfield, and Roach (33) in 1923 reported an 
investigation in which extracts of Derris elliptica were phown to have a 
high insecticidal value, partic-olarly for caterpillars. They were not 
so toxic to aphids. 
The dr^v- root itself may be used in a finely powdered condition 
worked up with water together with soap or other emulsifying reagents* 
As the pure poisons found in derris root are solids and only slightly 
solujle in water, their toxicity aopears to depend upon the degree 
of dirpcrsion, 
A biological method of determining insecticidal propcrtios 
quantit.-tivcly is described. It depends on dipping insects, for a con- 
stant pjriod of time (10 seconds), in known strengths of hii;hly dispersed 
suspensoids in dilute aqueous solutions of saponin. Results agreeing 
with those given by the chemical method alrc&dy described were obtained. 
It enabled the authors to compare extracts of dcrri?. with nicotine. To 
ccrtc'.in caterpillars tubatoxin and dcrrid arc shovm to be of the same 
order of toxicity as nicotine, ThcsQ' conclusions arc based on tests 
with the follov/ing insects: Caterpillars of the cabbage white butterfly, 
Pieri s brasuicao L, , the lackey moth, f.Iala,co3ma neustri a L. , the buff- tip, 
Phalera buccphala L. the gooseberry sawfly, Ncmat us ( Pteronidea ) rjbesii Scc^ , 
and those of another sawfly, Phymatojccra aterrima Klug. Tests were also 
made with larvae of the tomato moth. Poll a oloracoa L, , with silk-jorms, 
Bonby:: i.io ri L. and with Aphis rur.icis L. 
Howard (100) in 1923 reported the work of Bi shopp et al. against 
Hypo dc ma larvae in the backs of cattle. Over 98 percent of the grubs can 
bo killed vrith a general application to the backs of cattle of po\7dcrod 
dorris root. Awash consisting of 1 povrnd of derric-, 4 ounces of soap, 
and 1 gallon water has also given a percentage of kill above 95. 
