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NELSON, P. C. (2152) 
1927. THE PEHETHATION OF CONTACT OIL SPRAY INTO THE BREATHING- SYSTEM OF' 
AN INSECT. Jour. Scon. Ent. 20: 632-635. [Abstract in Rev. Appl . Ent . 
(A) 16: 85-86. 1928.] 
Flit and kerosene penetrate the tracheal tubes of "bees and 
flies to a greater extent than previous work with nicotine sulphate 
would indicate. 
17ALKER, H, T7-, and MILLS, J. E. (2153) 
1927. CHEMICAL WARFARE SERVICE, BOLL T7EEVIL INVESTIGATION. Indus, and 
Engin. Chem. 19: 703-711. 
Cotton boll weevils seemed to stand concentrations of gases 
entirely out of line with the known poisonous effect of the gas 
used. Weevils were found to survive after about 17 hours' exposure 
in pure carbon dioxide and hydrogen, and 4 out of 7 weevils recovered 
after 17 hours' submersion in water. Thus, weevils can live for some 
time without breathing oxygen. 
The toxic dosage' of nicotine per weevil was 0.00075 mg. at 
a concentration of 5 mg. per liter. The dosage was estimated from 
the toxic concentrations and times of exposure given, using the 
value 0.33 cc.as the amount of air breathed by a boll weevil in 
one hour (p. 709) . 
HEADLEE, T.J. (2154) 
1928. THE INTELLIGENT USE OF PYRETHRUM AND NICOTINE SPRAYS AND DUSTS 
AGAINST VEGETABLE INSECTS. N. J. State Hort. Soc. Proc, pp. 54-57. 
penetration of nicotine spray solutions in the past by use 
of ordinary soap has been limited. The surface tension of water 
solutions must be reduced and the so-called interfacial tension 
existing between the water solution and the integument of the insect 
must likewise be reduced. The surface tension of distilled water 
at a certain temperature is between 75 and 77 dynes and that of 
kerosene ranges from 28 to 33 dynes. Sodium oleate, when mixed properly 
with water, reduced the surface tension of water to between 28.5 
and 30 dynes. Kerosene readily enters the breathing pores of insects, 
and it was anticipated that a mixture of water, sodium oleate, and 
nicotine would do likewise, when the surface tension was sufficiently 
reduced. However, it wa.s found necessary to form a film over the en- 
tire insect in order to penetrate the pores because of the waxy coat- 
ing on the insect. In using nicotine sprays many insects may be 
killed by gas evolution that are not wet by the spray. 
WILSON, G. F. (2155) 
1928. NICOTINE AS AN INSECTICIDE. Amer. Jour. Pharm. 100 (6): 403-408. 
This is reprinted from Chemist and Druggist. It is a brief 
review but' no references are cited. 
