6 3c;. t7^ 



SB 

 818 

 C578 

 ENT 



issued November 29, 1912. 



U. S. DEPARTMENT OF AGRICULTURE, 



BUREAU OF ENTOMOLOGY— CIRCULAR No. 163. 



L. O. HOWARD, Entomologist and Chief of Bureau. 



HYDROCYANIC-ACID GAS AGAINST 



HOUSEHOLD INSECTS. 



L. O. HOWARD AXD C. H. POPENOE. 



64632° — 12 WASHINGTON : government printing office : 1912 





