13 
48. Electric Charges on Insecticide Particles. (10 min.) William 
Moore, New York, N. Y. 
Difference between static electric charges imparted by friction and charges due to 
absorbed ions. 
49. Miscible Oils and Oil Emulsions. (10 min.) J. G. Sanders, Phila¬ 
delphia, Pa. 
Discussion of emulsions and oils for emulsions and some of the pitfalls encountered 
in making and using oil emulsions. 
50. Quantitative Studies on the Toxicology of Arsenical Insecticides. 
(10 min.) F. L. Campbell, Forest Hills, Boston, Mass. 
By feeding individual caterpillars known quantities of arsenical solutions, quanti¬ 
tative relationships between dose and survival time were studied. 
51. A Preliminary Report on the Preparation of Insecticide Emul¬ 
sions with a Colloidal Clay. (5 min.) L. L. English, Ames, Iowa. 
52. Observations on Insects Developing Immunity to Insecticides. 
(10 min.) R. S. Woglum, Pasadena, Calif. 
Certain scale insects of citrus trees in California require heavier dosages of HCN for 
control than formerly. The areas of resistant scale are being extended. 
53. The Use of Fatty Acids as a Contact Insecticide. (10 min.) E. H. 
Siegler and C. H. Popenoe, Washington, D. C. 
An investigation of the aliphatic fatty acids has shown that certain members of the 
saturated series possess promising insecticidal properties as contact sprays. The 
studies have indicated that the toxicity of soaps when used as contact sprays is 
due to the release of the acid components through hydrolytic dissociation. 
54. “Gassing Ants”—Experiments in Killing the “Hormiguilla,’’ 
Myrmelachista ambigua vamulorum Wheeler, of Porto Rican Coffee 
Groves with Cyanide. (5 min.) George N. Wolcott, Barneveld, N. Y. 
55. The Distribution of an Insecticide Made Visible. (10 min.) 
(Lantern.) A. C. Morgan and R. G. Newborne, Clarksville, Tenn. 
A mixture of phenolphthalein and arsenate of lead was dusted on tobacco. A print 
of the leaves was taken on filter paper impregnated with an aqueous solution of 
sodium hydrate. The prints were immediately dried in an oven to prevent spread¬ 
ing of the indicator and were then paraffined for preservation. 
56. A Coloremetric Method for Showing the Distribution and 
Amount of Lead Arsenate upon Sprayed and Dusted Surfaces. (10 
min.) (Lantern.) C. C. Hamilton and C. M. Smith, College Park, Md. 
Insects Affecting Stored Products 
57. Present Status of the Use of Electricity in Control of Stored 
Product Insects. (10 min.) (Lantern.) E. A. Back and R. T. Cotton, 
Washington, D. C. 
Brief status concerning use of electricity. 
