BOOK -LICE OR PSOCIDS 
ANNOYING HOUSEHOLD PESTS 
E. A. BACK 
Entomologist in Charge of Stored Product and 
Household Insect Investigations 
Adult book-louse, about fifty times natural size. 
FARMERS’ BULLETIN 1104 
UNITED STATES DEPARTMENT OF AGRICULTURE 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. 9 February, 1920 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1920 
