INJtTRIOTTS INSECTS. 65 



they make rapid progress, and in places, where the colony is 

 firmly established, they will sometimes strip an orchard in a few 

 days, making it look as if a fire had passed over it. After feed- 

 ing about four weeks, they descend into the ground three or four 

 inches, where they remain in a chrysalis form, to emerge again 

 the next season. As the female is not provided with wings, 

 they do not spread very rapidly from one place to another. 



The attacks upon the canker worm should be chiefly made 

 upon the female, in her way from the ground up the trunk of the 

 tree. 



The common mode of protecting apple trees is to surround 

 the trunk with a belt or bandage of canvass, four or five inches 

 wide, which is then thickly smeared with tar. In order to prevent 

 the tar from soon becoming dry and hard, a little coarse train oil 

 must be well mixed with it ; and it should be watched and re- 

 newed as often as it appears necessary. This tarred belt catches 

 and detains all the females on their upward journey, and prevents 

 them from ascending the tree to lay their eggs. And if kept in 

 order it will very effectually deter and destroy them. When the 

 canker worm is abundant, it is necessary to apply the tarred 

 bandage in October, and let it remain till the last of May, but 

 usually it will be sufficient to use it in the spring. It is probable 

 that a mixture of coal tar and common tar would be the best 

 application ; as it is more offensive and will not so easily dry 

 and become useless, by exposure to the air and sun. Some 

 persons apply the tar directly to the stems of the tree, but this 

 has a very injurious effect upon the trunk. Old India rubber, 

 melted in an iron vessel over a very hot fire, forms a very adhe- 

 sive fluid which is not affected by exposure to the weather, and 

 is considered, by those who have made use of it, the best sub- 

 stance for smearing the bandages, as being a more effectual 

 barrier, and seldom or never requiring renewal. 



Mr. Jonathan Dennis, jr. of Portsmouth, Rhode Island, has 

 invented and patented a circular leaden trough, which surrounds 

 the trunk of the tree, and is filled with oil, and stops effectually 

 the ascent of the canker worm. There appear, however, to be 

 two objections to this trough, as it is frequently used ; one, the 

 escape of the oil if not carefully used, which injures the tree ; and 

 the other, the injurious effect of nailing the troughs to the bark 

 or trunk. They should be supported by wedges of wood driven 

 in between the trough and the trunk, and the spaces completely 

 filled up with liquid clay put on with a brush. The insects 

 must be taken out and the oil renewed, from time to time. For 

 districts where the canker worm greatly abounds, this leaden 

 trough is probably the most permanent and effectual remedy yet 

 employed. 



Experiments made by the Hon. John Lowell, and Professor 

 Peck, of Massachusetts, lead to a belief that if the ground, under 



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