138 
exposed similarly to the open air. As this powder had been left 
open for three or four days, it had doubtless greatly diminished in 
etticiency, and its action was less prompt than the smaller propor- 
tion suspended in water. In an hour many were still alive, but 
none were at all active. In four hours nine of the specimens could 
walk when placed upon their legs, and the remaining twenty-nine 
could all move their legs, but were otherwise helpless. In twenty- 
four hours all were dead but two, which could move their legs very 
slowly and feebly, and by the morning following all were dead. 
From the above experiments it is clear that in pyrethrum we have 
an extraordinarily effective insecticide for this species, and that it 
can be safely applied either in powder diluted with flour, or sus- 
pended in water,—in the latter case being sprayed or sprinkled upon 
the plants. 
The Kerosene Emulsion.—While this substance would be equally 
applicable either to the strawberry field, the vegetable garden, or 
the orchard, it was found worth while, also, to experiment with a 
somewhat cheaper insecticide, viz., the kerosene emulsion. This 
would, perhaps, be inapplicable to the strawberry field, except early 
in the season, as the kerosene would be apt to injure the flavor of 
the fruit; but in the garden and orchard it might be applied as 
readily as pyrethrum. 
For the first experiment, an emulsion of equal parts of kerosene 
and milk was mixed with twenty parts of water, the dilution con- 
sequently containing only two and one-half per cent. of kerosene. 
A spray of this was thoroughly applied to thirty-five adult plant 
bugs collected under leaves on the 22d of November, and in two 
hours nearly all seemed dead, but in two hours more three were 
commencing to revive. After another two hours, these three were 
running about, and two more were slowly reviving. In twelve hours 
four of the specimens had fully revived, one showed some signs of 
life, and the remainder were all motionless and apparently dead. 
As the specimens used in the preceding experiment were enclosed 
in a large bottle after being treated with the emulsion, a second 
similar experiment was tried upon forty-two individuals exposed to. 
the open air. These were stupid with cold when brought in from 
the field, but all revived in a warm room, and became extremely 
active. A fine spray of the dilution was appled until. all were 
thoroughly wetted. These were then placed on blotting paper in the 
bottom of a breeding cage. In three hours, fifteen were seemingly 
dead, not moving at all when touched, but the remainder of them 
were variously active, some of them crawling about. In another 
hour and a half only four were dead, seven of the others being 
torpid, and all the others scattered about the breeding cage, ap- 
parently unharmed. In twenty hours six of the bugs were dead, 
three showed some signs of injury, but the remainder seemed en- 
tirely unharmed. 
An experiment was next tried upon twenty-five specimens with a 
mixture of kerosene emulsion of twice the strength of that given 
above, containing, consequently, five per cent. of kerosene. These 
were placed under a large bell jar, so that they were exposed to the 
