374 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
Another comparison was made using mixtures containing molasses 
and the poison ingredient, sodium fluoride, with glycerin and without. 
The first lot of bran was wet with a mixture containing equal volumes of 
sodium fluoride solution (1 ounce in 4 ounces of water), glycerin and 
molasses. In the second lot the glycerin was replaced with water 
leaving identical amounts of poison and molasses. This experiment was 
primarily planned to see if glycerin affected the poisonous properties; 
but the two lots were exposed to get additional evidence on the attrac¬ 
tiveness. The results on the first night were: first mixture, 38; second 
mixture, 37. On the second night: first mixture, 16; second mixture, 3. 
POISON USED 
WITH EACH 
4lbs. BFIAN 
TOTAL 
EARWIGS 
IN LOT 
TOTAL 
AFTER 
DEAD EACH 
EVENING OF 
MORNING 
POI S ON l N6 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
zo 
No. F* 1 02. 
8S 
1 
23 
66 
77 
83 
83 
83 
83 
NaF 202. 
4-3 
1 
5 
28 
36 
42 
42 
42 
42 
43 
NaF 4 *oz- 
24 
7 
19 
23 
24 
NaF 8 oz. 
104 
14 
56 
101 
10 + 
CaST 1 02.. 
f 4 
1 
1 
1 
1 
1 
1 
s 
7 
CciFl 2 oz . 
1 20 
2 
2 
2 
2 
85 
CaFi 4 oz. 
59 
1 
l 
1 
1 
43 
CaF£ 8 oz. 
81 
8 
41 
56 
69 
73 
74 
75 
75 
75 
77 
AS 2 O 3 1 02. 
41 
1 
1 
1 
3 
4 
26 
37 
40 
AS 2 O 3 2 02. 
4-1 
1 
9 
24 
38 
41 
As 2 0 3 4 oz. 
74 
4 
34 
66 
74 
NCL3A3O4 2.02. 
9 
4 
6 
9 
NQ 3 ASO 4 4oz. 
33 
2 . 
8 
25 
28 
<31 
32 
33 
NQ3AS04. 802 
1 f 1 
7 
16 
65 
98 
III 
Table I. Showing toxicity of various amounts of sodium fluoride, calcium fluoride, arsenious oxide, 
and sodium arsenate for the European earwig. 
This, and the previous experiment both show that glycerin has con¬ 
siderable value as an ingredient to extend the attractiveness of a poison 
bait over a longer period of time. 
The killing effect of the two above mixtures was approximately 
equal. When mixed with bran they gave a poison bait containing about 
8 ounces of poison to 4 pounds of bran, equal to the strongest mixture 
shown in Table I. The mixture containing glycerin gave 45 dead and 1 
alive on the second morning, while the mixture without glycerin gave 
