'G8 OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 



It is very questionable whether the whitewash will destroy its eggs, but 

 there is every reason to believe that the friction of the brush and the 

 disengaging of many of the cocoons will cause the destruction of a 

 certain number. On our larger trees the greater number ol these 

 cocoons are never reached by such whitewashing, because they are upon 

 the higher limbs. The Web-worm cannot be affected by the practice, 

 as the hibernating chrysalids and cocoons are not found upon the 

 trunks. As against these negative results of whitewashing, however, 

 we must put the injurious results that follow indirectly ; because a great 

 many of the enemies of the defoliators are destroyed by whitewashing. 

 This is particularly the case with the egg-masses of spiders and many 

 of the softer and more delicate cocoons of parasites. 



BIRDS : THE ENGLISH SPARROW. 



All four of these insects have a certain immunity from the attacks 

 of birds : No. 1 by virtue of an offensive odor ; No. 2 by the protection 

 of its bag; Nos. 3 and 4 by the protection afforded by the hairs of the 

 caterpillars, which are also mixed into their cocoons. A few native 

 birds we have seen occasionally feed upon Nos. 3 and 4, but the En- 

 glish sparrow, to which, being emphatically a city bird, we should look 

 for help, has never been known to attack any of them. In fact, we 

 noticed and announced many years ago that in some of the northern 

 cities (as Boston and Philadelphia) the increase of the Orgyia was 

 indirectly a result of the increase of the English sparrow, which feeds 

 in the breeding season upon smooth worms less harmful to our trees, 

 and thus gives better opportunity for the rejected Orgyia to increase, 

 a result still further promoted by the habit of driving away the native 

 birds which the English sparrow is known to have. The same reasoning 

 will hold true in respect of the Web-worm ; and, putting all sentiment 

 aside, we may safely aver that this bird is an impediment rather than 

 an aid in preserving our trees from their worst insect defoliators. There 

 is every reason to believe that the Bag-worm is carried, when young, 

 from tree to tree upon the claws and legs of the bird, and its dissemina- 

 tion is thus aided and its destruction rendered more difficult; while the 

 yellow suspended cocoons of the Meteorus hyphantrice (the most im- 

 portant of the parasites of the Web-worm) are sought by the sparrow, 

 probably being mistaken for grains of wheat. 



While our feathered friends, owing to the sparrow's pugnacity, are 

 now things of the past, and can only be seen in the spring when they 

 pass through the cities in their migrations to more peaceable nesting 

 places, yet something might be done to encourage their stay. Nesting 



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