CC OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 



termed salmon brick, trim it to an egg shape; then take two soft wires, 

 cross them over this brick, wrapping them together around the oppo- 

 site side so as to firmly secure it ; now tie this end to a long stick, such 

 as the boys get at the planing mills, by wrapping around it; then soak the 

 brick in coal-oil, light it with a match, and you are armed with the best 

 and cheapest weapon known to science. Holding this brick torch under 

 the nests of caterpillars will precipitate to the sidewalk all the worms 

 on one or two trees at least from one soaking of the brick, and it can be 

 repeated as often as necessary. Then use a broom to roll them under 

 it and the work will be done, the controversy ended, and the tree saved.' 7 

 Asbestos may also be used to advantage, and a little thorough work 

 with some simple torch at the right time will in nearly every case obvi- 

 ate the necessity of the more expensive remedies later in the season, 

 when the worms of the first brood have grown larger or when the sec- 

 ond brood has appeared. 



mulching-. 



After a bad caterpillar year, a little judicious raking together of leaves 

 and rubbish around the trunks of trees which have been infested, at the 

 time when the worms of the second brood are about full-grown and be- 

 fore they commence to wander, will result in the confinement of a large 

 proportion of the pupa? to these limited spaces, where, with a little hot 

 water or a match, they can readily be destroyed during the winter. 

 Many of the caterpillars, of course, reach the ground by dropping pur- 

 posely or falling accidentally from the branches, but the great majority 

 descend by the trunk, and, finding the covenient shelter for pupation 

 ready at the foot of the tree, go no farther. This has been tested on 

 the Department grounds the past season, and is mentioned as a method 

 of riddance supplementary only to others. 



INFLUENCE OF TREE-BOXES. 



However necessary it may be in cities to protect trees, by means of 

 tree-boxes, against bodily injury, chiefly committed by mischievous 

 boys and loafers, such protection should only be afforded for a limited 

 time, or long enough for the growing tree to attain a sufficient thickness 

 to prevent its being broken by any ordinary accident. After such a 

 thickness has been reached the boxes ought to be discarded. They are 

 unnatural, and both injurious to the tree and unpleasant to the. eye. A 

 great number of trees are forever iujured by such boxes, and the great 

 increase of some kinds of insects is solely due to them. For instance, 

 the Maple Bark-borer (Trochilium acerni) is almost solely confined to 

 the injured bark of maple trees protected by boxes, and is scarcely ever 

 found in normally growing trees. Such tree-boxes furnish good shelters 

 for the formation of cocoons, and afford winter quarters for many nox- 

 ious insects. The Web-worm under consideration makes excellent use 

 of them. A small Box Elder, with a trunk of about 4 inches in diarne- 



