574 Insect Powder. — [ September, 
reach the plants again and hence perish. By applying the pow- 
der freely in the evening and giving the plants a thorough 
syringing in the morning, they may in the worst cases be almost 
freed from Aphides by a single application ; it is better, however, 
to repeat its use the next evening, so.as to make sure work. 
The powder does not appear to kill this Aphis as it does the flies, 
For the purpose of testing this point we placed a number of 
them in an open glass cell of a microscope slide and powdered 
them thoroughly, and found some of them alive after two days of 
such severe exposure to its influence. Having recently found a 
plant literally swarming with the green Aphis, so that the sight 
of it was almost disgusting, we submitted it to the action of this 
powder one afternoon, having previously spread a large piece of 
white paper under the plant, so that the effect of the powder on 
the insects might be distinctly seen. Almost immediately they 
began to fall on the paper, and in less than ten minutes a 
hundred or more of them were lying on their backs or crawling 
sluggishly about. In the course of half an hour some four or 
five hundred had fallen on the paper, and when the plant was 
examined again the following morning, there remained but very 
few on it, and most of these were removed by a slight syringing. 
We have had the powder used in green-houses by some of our 
friends, who also report its success. This matter is well worthy 
the attention of all those who indulge in window gardening or 
who grow plants in small conservatories attached to dwellings, 
since if this proves an efficient and economical substitute for 
tobacco smoke, it will save much annoyance and some loss. 
Success will necesarily depend on the quality of the material 
used, but after the experiments we have tried, we feel confident 
that with good Dalmatian powder there need be no failure. It 
will be interesting to learn, as opportunity offers, how moths and 
other insects will be affected by the use of insect powders. If 
the beautiful specimens which sometimes fly into our rooms at 
night can be drugged in this way and captured without a strug- 
gle, we may add many a perfect specimen to our collections 
which would otherwise be more or less defaced. There is quite 
_ a field for experiment here.— Canadian Entomologist. 
