THE STATE ENTOMOLOGIST. 151 



Artificial Kemedies — From the natural history of this Bag-worm 

 it becomes obvious, that by plucking the cases in the winter time, 

 and burning them, you can effectually rid your trees of them, and I 

 advise all who desire healthy trees to do this before the buds begin to 

 burst in the spring. Where this is not done the worms will continue 

 to increase, and partly defoliating the tree each year, slowly, but 

 surely, sap its life. 



In conversation some time since with Mr. Edward Cook, who is 

 superintending the improvements in Washington Park, St. Louis, I 

 showed him that every one of the young trees that had been lately 

 planted there had from six to a dozen of these Bag-worms hanging 

 from their twigs. I explained to him that the trees would never thrive 

 with these parasites, and that, prevention being easier than cure, he 

 had better have them plucked off at once, while they were within 

 reach. He informed me afterwards that he had gathered two barrels 

 full from these trees, but there are many yet left, which should be 

 removed before spring. 



THE AILANTHUS WOEM— Larva of (Eta compta, Clem., Plate 2, 

 Eigs. 22 and 23. 



(Lepidoptera, Tineidae.) 



The Ailanthus is highly prized in most of our cities as a shade tree, 

 and though there certainly are other trees as quick growing, and as 

 hardy, which might advantageously take its place, yet as it has an al- 

 most perfect immunity from the attacks of the Bag-worm and continues 

 to be grown, it will be of interest to know what insect enemies it has. 

 Fortunately it has very few, but every St. Louisan must have noticed 

 last fall that nearly all the young Ailanthus trees around the city, and 

 in the parks, looked black and seared as though they had been 

 scorched by fire. Few probably divined the cause of this phenomen- 

 on, but it was the work of the worm which is the subject of this 

 chapter. 



This worm is slender and of a very dark olive-brown color, with 

 white longitudinal lines. During the months of August and Septem- 

 ber it may be found of all sizes, living in communities of from five to 

 thirty individuals within a slight silken web. Did they but feed on 

 the leaves their injury to the tree would be slight, but they have the 

 miserable habit of gnawing the leaf stalk in two, and of severing 

 the leaf, and causing it to turn black ; thus marring the looks of large 

 trees and killing many seedlings outright. When the worm is full 

 grown it suspends itself in the middle of the loose web and changes 

 to a chrysalis about ^ inch long and of a dull smoky-brown color. 

 The chrysalis skin is so very fine, that as the future moth develops 



