LEPIDOPTERA. 339 



of Watertown, Mass., has used, for this purpose, a mixture of 

 water and oil-soap (an article to be procured from the manufacto- 

 ries where whale oil is purified;) in the proportion of one pound of 

 the soap to seven gallons of water ; and he states that this liquor, 

 when thrown on the trees with a garden engine, will destroy the 

 canker-worm and many other insects, without injuring the foliage 

 or the fruit. Jarring or shaking the limbs of the trees will dis- 

 turb the canker-worms, and cause many of them to spin down, 

 when their threads may be broken off with a pole ; and if the 

 troughs around the trees are at the same time replenished with 

 oil, or the tar is again applied, the insects will be caught in their 

 attempts to creep up the trunks. In the same way, also, those 

 that are coming down the trunks to go into the ground will be 

 caught and killed. If greater pains were to be taken to destroy 

 the insects in the caterpillar state, their numbers would soon 

 greatly diminish. 



Even after they have left the trees, have gone into the ground, 

 and have changed their forms, they are not wholly beyond the 

 reach of means for destroying them. One person told me that 

 his swine, which he was in the habit of turning into his orchard in 

 the autumn, rooted up and killed great numbers of the chrysalids 

 of the canker-worms. Some persons have recommended digging 

 or ploughing under the trees, in the autumn, with the hope of 

 crushing some of the chrysalids by so doing, and of exposing 

 others to perish with the cold of the following winter. If hogs are 

 then allowed to go among the trees, and a few grains of corn are 

 scattered on the loosened soil, these animals will eat many of the 

 chrysalids as well as the corn, and' will crush others with their 

 feet. Mr. S. P. Fowler* thinks it better to dig around the 

 trees in July, while the shells of the insects are soft and tender. 

 He and Mr. John Kenrick, of Newton, Mass., advise us to re- 

 move the soil to the distance of four or five feet from the trunk 

 of the trees, and to the depth of six inches, to cart it away and 

 replace it with an equal quantity of compost or rich earth. In 

 this way, many of the insects will be removed also ; but, unless 



* See " Yankee Farmer" of July 18, 1840, and " New England Farmer" of 

 June 2, 1841, for some valuable remarks by Mr. Fowler. 



