THE SPARROW'S USEFULNESS IN AMERICA. 81 



writer asserts that "here in Boston the sulphur-colored 

 caterpillars have ceased to disgust us with their odious 

 presence, and we no longer fear for the safety of our 

 elms as we did in 1869," etc., Mr. Purdie inquires, 

 "Why these caterpillars on our trees? "With more spar- 

 rows than ever before, and more native species, how can 

 it he? These crawling things come from eggs that all 

 last fall, winter, and spring, the pretty little sparrows 

 should have eaten. They were laid by the wingless 

 female imago, which should also have been devoured. 

 The chrysalis must now be swallowed as a dainty 

 morsel! But no; not one is molested by Passer domes- 

 ticus." 



Still further our informant remarks: "Mr. Galviu 

 must have noticed this and re-engaged his corps of tree- 

 scrapers, for on the 18th instant, men appeared on the 

 Common, each armed with a sharp-pointed pole with 

 which then and since they destroyed the caterpillars and 

 their cocoons, and the trees bear scars where each victim 

 was effectively impaled. But those within ground-reach 

 only are disposed of. Others on the limbs of the larger 

 trees are left for the sparrows to enjoy. In a week or 

 two more the transformation will be complete, the male 

 moths will be seen flying about, and the unobserved 

 female, simply crawling from the inside to the outside 

 of her cocoon, will there deposit her eggs, the same to 

 develop next season into the destructive stage of exist- 

 ence." 



Mr. Purdie does not leave the subject here. After 

 showing that the trees of the Common are provided with 

 one or more occupied boxes to each tree, he leaves the 

 scene and invites the reader to a place on Bowdoin 

 Street, where stand six trees, maples and horse-chestnuts, 



