EXPEKIMENTS AGAINST BEDBUGS. 7 



TESTS AGAINST BEDBUG EGGS. 



The eggs used in these experiments had been deposited on pieces 

 of paper or cloth. These were thoroughly sprayed or dusted with the 

 materials to be tested and then placed in jars covered with cheese- 

 cloth. Kerosene oil was the only material used which was found to be 

 completely effective, not one of the eggs sprayed with this material 

 hatching. The fact that the eggs sprayed with gasoline apparently 

 hatched in a perfectly normal manner indicates that this material, 

 although effective against bedbugs, vaporizes so rapidly that it does 

 not penetrate the eggshell and reach the embryo, and that the 

 evaporation is so complete that not enough oil remains, at the end of 

 six days, to kill the newly hatched insects. 



Mercuric chlorid, either as a dust or in a 1.35 per cent spray, ap- 

 peared to have no effect on the eggs, as the young bugs emerged at 

 approximately the same time as those from the untreated eggs. 

 Where this material was applied as a dust, enough was present to 

 kill all of the insects as soon as they had left the eggs, but the amount 

 left by the 1.35 per cent solution apparently was not great enough to 

 kill them. 



SUMMARY. 



1. The hydrocarbon oil sprays were found to be very effective 

 against bedbugs, killing, in most cases, 100 per cent within 48 hours. 



2. Coal-tar creosote emulsions were effective, when used undiluted, 

 but their effectiveness fell very rapidly when they were diluted. 



3. Mercuric chlorid, as a dust and in a 6 per cent water solution, 

 was found to kill 100 per cent of the treated insects. 



4. Pyrethrum was found to be very effective against bedbugs, while 

 pyrethrum stems were of little or no practical value. 



5. Tobacco powders, containing as high as 5.26 per cent of nicotine, 

 were found to be of little or no value. 



6. Hellebore was found to be absolutely ineffective against bedbugs. 



7. Twenty miscellaneous powdered mixtures containing more than 

 one active ingredient were tested and found to be more or less effec- 

 tive, depending on the amount of the active ingredients present. 



8. Acetic acid, ammonia water, coal-tar oil (chlorinated), cotton- 

 seed oil, glycerol, kerosene, linseed oil, nicotine, oil of pine needles, — 

 sabadilla seeds, turpentine and mercuric chlorid were found to be 

 effective. 



9. Twenty miscellaneous materials were found to be ineffective. 



10. Sulphur fumigation, at the rate of 0.97 pound to 1,000 cubic feet 

 of room space, was found to kill 100 per cent of the treated insects. 



11. Three miscellaneous fumigants were found to be ineffective. 



