-11- 
These results are also referred to in the annual report of the New 
Jersey Agricultural Experiment Station (292) for 1935. 
Fischer and Nitsche ( 134- ) in 1935 reported tests on fifth instars 
with rotenone and various derris preparations. Pure rotenone 0.15 gm. 
in 98 cc. of neutral Turkey-red oil plus 2 cc. of acetone diluted with 
water 6:94. killed 9,7«5 percent of the silkworms within 2 days. 
Tischler ( 4-13 ) in 1935 studied the mechanism of how derris kills 
insects. Studies on the heart ratea of various insects (including 
silkworms) showed that the rate of pulsation was markedly decreased 
before the insects exhibited incoordinated movements. Other tests 
made with silkworms led to the conclusion that derris inhibits oxygen 
utilization by the tissues and that its detrimental effects are general 
rather than specific to any organ. 
Trappmann and Nitsche ( 4-17 ) in 1935 reported that rotenone sprays 
gave 98-percent and rotenone dusts 100-percent mortality of fourth instars 
of the silkworm after 8 days. Dosage was regulated to give a deposit of 
0.18 mg. of rotenone per 500 cm. . 
Klinger ( 237 ) in 1936 reported the results of toxicity tests carried 
out with pyre thrum extract and with rotenone and derris root on fourth 
instars of a number of Lepidoptera. Fifteen-percent petroleum extracts of 
pyrethrum and of rotenone were dilutee to 0.15 percent, with Turkey-red 
oil for spray tests and with talc for dusts. These talc and Turkery-red 
oil preparations served as standard solutions, beirg diluted further for 
the tests. The spray balance described by Trappmann and Nitsche and the 
dusting bell used by Lang and Welte were employed for measuring the dosages, 
The concentrations used in the actual tests -vere 0.00015 gm. o r pyrethrin 
or rotenone in 100 gm. of dust (on Al c cm. 2 ) and 0.00018 gm. in 100 gm. 
of spray (on 500 cm. 2 ). I n some instances it was necessary to double or 
treble this concentration.. The standard agents were kept in well-closed 
containers in the dark and no loss in toxicity was apparent after 4 to 5 
months. The tests were carried out at room temperature (19° to 25° C). 
Tho spray gave 100-percent and the dust 95-percent mortality of 20 fourth 
instar silkworms a r ter 8 days. Derris dust caused 100-percent mortality 
in 6 days. Rotenone was less effective than pyrethrum against most of 
the insects. Derris root was markedly more toxic than rotenone, . showing 
that the other active constituents of the root — tephrosin, deguelin, 
and toxicarol — are of importance. The toxicity of the insect poisons 
in derris root, expecial ly rotenone, was shown to be due to a hindering 
of cell respiration and not to any action on the nervous system such as 
that caused by the pyrethrins. 
Citheroniidae 
Anisota senatorja (A. & S.\ the orange-striped oak vorm 
Two small oak trees, on which about 300 caterpillars of this 
species were feeding, were sprayed thoroughly with derris at th> r I 
