INSECTICIDES 361 



30. Harvill, E. K., A. Hartzell, and J. M. Arthur, "Toxicity of piperine solutions to 



houseflies," C. B. T. I., 13 : 87-92 (1943). 



31. Klinger, H., "Die insektizide Wirkung von Pyrethrum und ihre Abhiingigkeit vom 



Insektenkorper," Arb. ii. Physiol, u. Angew. Ent. Berlin-Dahlem, 3 : 115-151 

 (1936). 



32. Krliger, F., " Untersuchungen fiber die Giftwirkung von dalmatischem Insekten- 



pulver auf die Larven von Corethra plumicomis," Zeitschr. Angew. Ent., 18 : 344- 

 353 (1931). 



33. McKenna, G. F., and A. Hartzell, "Effect of wetting agents in increasing the effi- 



ciency of sprays used in control of Japanese beetle," C. B. T. I., 11 : 465-471 

 (1941). 



34. Moore, W., and S. A. Graham, "Physical properties governing the efficiency of con- 



tact insecticides," J. Agric. Res., 13 : 523-538 (1918). 



35. Murphy, D. F., and C. H. Peet, " Insecticidal activity of ahphatic thiocyanates. 



I. Aphis," /. Econ. Ent., 25 : 123-129 (1932). 



36. , , "Insecticidal activity of ahphatic thiocyanates. II. Mealy bug," Ind. 



Eng. Chem., 25 : 638-639 (1933). 



37. Seil, H. A., "Estimation of pyrethrins," Soap, 10(5) : 89, 91, 111 (1934). 



38. Speyer, E. R., "Entomological investigations," Nursery & Market Card. Indus. 



Develop. Soc. Ltd. Exp. & Res. Sta. Ann. Rept., 9(1923) : 69-81 (1924). 



39. Staudinger, H., andL. Ruzicka, "InsektentotendeStoffe. X. tJber die Synthese von 



Pyrethrinen," Helv. Chim. Acta, 7 : 448-458 (1924). 



40. Tattersfield, F., R. P. Hobson, and C. T. Gimingham, "Pyrethrin I and II. Their 



insecticidal value and estimation in pyrethrum {Chrysanthemum cinerariaefo- 

 lium). I," /. Agnc. Sci., 19 : 266-296 (1929). 



41. Wilcoxon, F., "The determination of pyrethrin I," C. B. T. I., 8 : 175-181 (1936). 



42. , and A. Hartzell, "Some factors affecting the efficiency of contact insecticides. 



I. Surface forces as related to wetting and tracheal penetration," C. B. T. I. 3 : 

 1-12 (1931). 



43. , ," Some factors affecting the efficiency of contact insecticides. III. Fur- 

 ther chemical and toxicological studies of pyrethrum," C. B. T. I., 5 : 115-127 

 (1933). 



44. , , "The active principles of pyrethrum and their action on insects," Soap, 



9(5) : 85-87, 99, 101 (May, 1933). 



45. , , "Further experiments on organic thiocyantes as insecticides," C. B. T. I., 



7 : 29-36 (1935). 



46. , , "Experiments on greenhouse fumigation with /3,/3'-dichloroethyl ether," 



C. B. T. I., 10 : 47-56 (1938). 



47. , , and F. Wilcoxon, "Insecticidal properties of extract of male fern {Aspi- 



diumfilix-mas [L.] Sw.)," C. B. T. I., 11(1939) : 1-4 (1940). 



48. , , and W. J. Youden, "Greenhouse fumigations with naphthalene solu- 

 tions," C. B. T. I., 6 : 461-469 (1933). 



Note: The common greenhouse red spider in the United States is now recognized as 

 Tetranychus bimaculatus Harvey. 



