LEPIDOPTERA. 337 



able to creep in an inverted position, beneath the smooth and 

 sloping surface. This method will also prove too expensive for 

 general adoption, even should it be found to answer the purpose. 

 A belt of cotton-wool, which it has been thought would entangle 

 the feet of the insects, arid thus keep them from ascending the 

 trees, has not proved an effectual bar to them. Little square or 

 circular troughs of tin or of lead, filled with cheap fish oil, and 

 placed around the trees, three feet or more above the surface of 

 the ground, with a stuffing of cloth, hay, or sea-weed between 

 them and the trunk, have long been used by various persons in 

 Massachusetts with good success ; and the only objections to 

 them are the cost of the troughs, the difficulty of fixing and keep- 

 ing them in their places, and the injury suffered by the trees 

 when the oil is washed or blown out and falls upon the bark. 

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

 obtained a patent for a circular leaden trough to contain oil, offer- 

 ing some advantages over those that have heretofore been used, 

 although it does not entirely prevent the escape of the oil, and 

 the nails, with which it is secured, are found to be injurious to 

 the trees. These troughs ought not to be nailed to the trees, 

 but should be supported by a few wooden wedges driven between 

 them and the trunks. A stuffing of cloth, cotton, or tow, should 

 never be used ; sea-weed and fine hay, which will not absorb the 

 oil, are much better. Before the troughs are fastened and filled, 

 the body of the tree should be well coated with clay-paint or 

 white-wash, to absorb the oil that may fall upon it. Care should 

 be taken to renew the oil as often as it escapes or becomes filled 

 with the insects. These troughs will be found more economical 

 and less troublesome than the application of tar, and may safely 

 be recommended and employed, if proper attention is given to the 

 precautions ahjove named. Some persons fasten similar troughs, 

 to contain oil, around the outer sides of an open box enclosing 

 the base of the tree, and a projecting ledge is nailed on the edge 

 of the box to shed the rain ; by this contrivance, all danger of 

 hurting the tree with the oil is entirely avoided. In the " Man- 

 chester Guardian," an English newspaper, of the fourth of No- 

 vember, 1840, is the following article on the use of melted Indian 

 rubber to prevent insects from climbing up trees. "At a late 

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