Bui. 60, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate III. 



Laboratory Methods in the Cotton Boll Weevil Investigations. 



Fig. 5.— Camera stand designed for both horizontal and vertical work. Fig. 6.— Arrangement 

 used in securing black backgrounds with camera horizontal. Fig. 7.— Chart making with 

 stereopticon for projecting image. Fig. 8.— Chart made from negative image projected by 

 electric light through copying camera. (Original.) 



