THE CANADIAN ENTOMOLOGIST. 43 



uneasiness and begin to drop from the plants to the ground, and in the 

 course of an hour or two the larger portion of the enemy's forces will be 

 found lying sprawling on the earth in the pots or on the shelves and floor 

 of the house, where, probably partly from the stupefying effects of the 

 powder and partly from their natural inability to find their way to any 

 given point, they fail to reach the plants again and hence perish. By 

 applying the powder 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 necessarily depend on the quality of the material used, but 

 after the experiments we have tried, we feel confident that with good Dal- 

 matian 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 struggle, 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. 



