348 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



negligence and mismanagement of the owners of the forests and the 

 manufacturers of forest products; 



The absolute necessity of expert entomological advice as a guide to 

 doing the proper thing at the proper time and at the least expense 

 to secure the best results. 



CYANIDE AS AN INSECTICIDE 



By R. S. WoGLUM, U. 8. Bureau of Entomology, and 

 William Wood, Lo.s Angeles Hoiiicultural Commission 



Cyanide of potassium has been used for many years as one of the 

 ingredient chemicals for obtaining hydrocyanic acid gas, the most 

 powerful and successful of gaseous insecticides. The writers are not 

 aware of cyanide of potassium having been previously suggested in 

 literature as an insecticide in itself. From experimentation we have 

 found it most efficient in the destruction of a common form of red ant. 



In the rear yard of the California Citrus Substation, of the United 

 States Bureau of Entomology, at AVhittier, is a spot of hard-packed 

 bare ground about 20 by 30 feet. This ground contained several 

 scores of exit burrows of a common red ant. During the cooler part 

 of the day ants were so numerous on this spot that it was impos- 

 sible for a person to walk here without stepping on as many as fifty 

 at every move. The insect became such a nuisance that steps were 

 taken for its control. Carbon bisulphide was first tried, but the ex- 

 pense of the material made it prohibitive for so many burrows. Later 

 a spray of cyanide of potassium, one half of an ounce to a gallon of 

 water was used on part of this ground and resulted in destroying 

 almost all ants running about on the part sprayed. This solution, 

 although successful, acted so slowly that it was decided to double its 

 strength. The next evening when the ground was seemingly alive 

 with ants the entire spot was thoroughly sprayed with a solution of 

 one ounce to the gallon of water. This not only very quickly de- 

 stroyed all ants on the ground, but also such as emerged from the 

 burrows several minutes afterward were overcome by the fumes which 

 were given off from the damp ground. The following day less than 

 a quarter as many ants were moving over the ground as previously. 

 The dead ants had been collected into heaps at different places by 

 those which remained alive. 



No farther efforts to exterminate were made for two weeks, at the 

 end of which the ants had become almost as numerous as ever. Then 

 a pit large enough to hold a quart of solution was hollowed out at the 



