122 THE ENGLISH SPARROW IN AMERICA. 



six weeks of the early part of the growing season, nothiug being seen of it during 

 summer and fall, as the worm descended into the ground to undergo its transforma- 

 tions. On account of the apterous nature of the female moth, the injuries of the 

 species are also easily prevented, since tarred bandages or troughs of oil around the 

 trunk of a tree will prevent her ascent as she issues from the ground in early 

 spring. Such troughs were, indeed, at one time in such common use for this purpose 

 in Boston, Cambridge, and Philadelphia that when, some years ago, the elm trees 

 in Baltimore were found to be defoliated, the authorities at once ordered them to be 

 similarly treated. The city fathers found out afterwards that they had paid dearly 

 for their haste and want of special knowledge in that their trees were suffering, not 

 from the Canker-worm, but from an Imported Elm-leaf Beetle (Galeruca calm ari en sis), 

 which, having wings in both sexes, was not affected by the troughs. But, to come 

 back to the Sparrows. They did, according to report, accomplish some good in clearing- 

 off the Canker-worm, though during late visits to Cambridge and other cities adorned 

 with grand old elms, I found the tarred bandages still in use, thus indicating that 

 our imported " Spatz " was not a perfect antidote for the evil. The interesting point, 

 however, to which I wish to call your attention is that while the Canker-worm has 

 been kept more or less in check by the activity of these saucy little birds, another 

 insect, formerly scarcely noticed, has taken its place. Not only during the spring 

 months, but throughout the growing season, the people are now annoyed by the hairy 

 larva of the White-marked Tussock-moth (Orgyia ■ leucostigma), there being several 

 generations annually. This is a prettier creature to look at, but it has the same un- 

 pleasant Taculty of dropping upon passers-by as had the plainer Canker-worm. The 

 female is also like that of the Canker-worm, wingless, but the transformations of the 

 species take place above ground, and she lays her eggs upon the outside of her cocoon, 

 so that there is no such simple and available preventive in this case as in the other. 

 Moreover, the Tussock-moth is much the more general feeder, and occurs on some 

 trees which the Canker-worm never affected. As a consequence, this hairy worm has 

 in many places become a greater scourge than was formerly the Canker-worm. It 

 not only defoliates the trees, but covers and defaces them with its cocoons, which it 

 also plasters upon fences, railings, and even houses. 



I have been quite interested in observing the unprecedented multiplication of this 

 hairy worm since the English Sparrow became so abundant, and we may well ask, in 

 the expressive language of the time, "does protection protect?" There is nothing 

 very surprising in these facts, because they are very much what naturalists expected. 

 You can not encourage the undue multiplication of any one species of animal without 

 causing a decrease of some other species, and the opposite of this proposition holds 

 equally true. The hairy larva spoken of is distasteful to the Sparrow. The multipli- 

 cation of this bird, in causing a decrease in the Canker-worms, presents a wider field 

 for the Tussock-moth, and diminishes the competition in the struggle for existence 

 which this last, like all creatures, is subject to. The same increase of the Sparrows 

 necessitates a decrease of the native birds, some of which, doubtless, fed upon the 

 Tussock-moth, and notwithstanding Professor Brewer's assertion to the contrary, I 

 think the evidence shows such to have been the case. 

 Believe me, yours, very truly, 



C. V. Riley. 



Washington, D. C, 



December 16, 1878. 



It were premature to generalize from the study of the material so far 

 examined, which I hope is but the beginning of a more extended study. 

 For this purpose it is desirable that stomachs should be obtained from 

 as many different parts of the country as possible, and especially during 

 the spring of the year, when the bird probably takes the largest part of 

 its insect food. Exact location and date are very essential, as this Spar- 



