428 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 11 
contact insecticide killing the roaches in two to ten days through 
contact of the powder alone. 
Table No. 3. Boric Acid and Borax and Sugar Compared 
Without other food With other food 
Date 
Boric acid 
Borax and sugar 
Boric acid 
Borax and sugar 
Sept. 13 
Exp’t started 
Sept. 14 
0 dead 
Sept. 15 
2 dead 
Sept. 16 
14 dead 
Sept. 17 
3 dead 
Sept. 18 
4 dead 
Sept. 19 
0 dead 
Exp’t started 
Sept. 20 
0 dead 1 
0 dead 
Sept. 21 
1 dead 
3 dead 
Sept. 22 
3 dead 
5 dead 
Sept. 23 
1 dead 
6 dead 
Sept. 24 
1 dead 
3 dead 
Sept. 25 
Exp’t started 
1 dead 
Exp’t started 
0 dead 
Sept. 26 
2 dead 
Total 30 
2 dead 
0 dead 
Sept. 27 
13 dead 
19 dead 
0 dead 1 
Sept. 28 
12 dead 
9 dead 
6 dead 
Sept. 29 
3 dead 
Total 30 
1 dead 
Sept. 30 
Total 30 
0 dead 
Oct. 1 
0 dead 1 
Oct. 2 
6 dead 
Oct. 3 
Total 30 
At another time pieces of apple spread with borax were placed in a 
cage containing 126 roaches that had been without food for twenty-four 
hours. This was to determine the length of time required to kill the 
roaches when they were forced to eat borax in order to obtain other 
food. In this case eight days were required to kill all the roaches, al¬ 
though most of them were dead within the first four days. 
Table No. 4. Borax Spread on Apple 
Date 
No. of roaches dead and removed 
Sept. 20 
Experiment started 
Sept. 21 
14 
Sept. 22 
57 
Sept. 23 
29 
Sept. 24 
20 
Sept. 25 
4 
Sept. 26 
1 
Sept. 27 
0 
Sept. 28 
1 
Total 8 days 
126 roaches 
1 On these dates the borax and sugar mixture was stirred up in order to freshen it. 
Apparently this made it more effective for more dead roaches were found soon after. 
