THE INSECT WORLD. 



winter, the cuttings, of course, to be promptly destroyed. Thus 

 the number of individuals to start new infestation in spring 

 will be greatly reduced. They breed agamically throughout the 

 summer, and bring forth the sexed individuals late in fall or 

 early in winter. I found them in New Jersey still ovipositing 

 during the first week in December. Where pruning is not de- 

 sirable, much can be done by spraying the trees, as soon as the 

 eggs have hatched, with kerosene emulsion, — say, one part in 

 t^velve or thirteen of water. Both of these species lay a number 

 of eggs, but how many has not, I believe, been actually deter- 

 mined. The species that infests hops has been already mentioned, 

 and the best remedy against it is the total destruction of the vines 

 immediately after the hops have been gathered, which will head 

 off the production of the sexes. If this is delayed, spraying the 

 plum-trees in fall or early in the spring before the hop-vines have 

 made much start will be of great advantage. When the insects 

 infest such plants as wheat, rye, or oats, it becomes difficult to 

 adopt measures likely to be of much benefit. They multiply so 

 rapidly, and the task of spraying a wheat-field is so enormous, 

 that it is hardly worth while to recommend it. In such cases 

 we must stimulate, to assist the plants in outgrowing injury, by 

 applying such readily soluble fertilizers as nitrate of soda. This 

 gives additional vigor to the plant, enabling it to sustain the 

 attacks of the insect and mature a crop as well. Harvesting 

 should not be delayed longer than absolutely necessary, unless it 

 is observed that the enemies of the plant-lice are getting the bet- 

 ter of them, and in that case nothing will be lost by leaving the 

 grain as long as desirable. The aphid infesting cucumber- and 

 melon-vines has been recently determined to be the same as one 

 of those infesting oranges, and as that which frequently injures 

 cotton. It has also been found on the strawberry, and seems, 

 indeed, to be a very general feeder, passing the winter upon 

 such wild plants as remain more or less green. Under favorable 

 circumstances it increases rapidly in spring, and a migration 

 starts to cultivated fields. Against this insect on melon-vines 

 we can use bisulphide of carbon, covering the plants with a bowl 

 or other covering, and evaporating a small quantity beneath it. 

 This will kill the aphids in about an hour, and, though the pro- 

 cess is slow, it has the advantage of being completely effective. 



