62 BULLETIN 286 



to hold it in check for the last fifty years, and it is equally evident that 

 for the past three or four years these forces have been partly or wholly 

 inoperative. 



The testimony regarding the activity of the English sparrow in 

 exterminating this pest in cities seems to show rather conclusively 

 that this much-disliked bird did actually bring about the destruction 

 of this insect. Nearly every writer on the snow-white linden moth 

 makes acknowledgment to the sparrow and declares that the cities 

 owe their freedom from this insect to that bird. We take pleasure in 

 again calling attention to this little-known meritorious work of the 

 English sparrow. 



Mr. William H. Broadwell in describing the visitation of the snow- 

 white linden moths at Newark, N. J., on the night of July lyth, 1908, 



as "a July blizzard," has the follow- 

 ing to say regarding the work of the 

 * sparrows in destroying this insect: 



"Early the following morning, under 

 the lamps, the wings were on the 

 ground as thick as apple blossoms 

 after a storm, showing that the spar- 

 rows had not forgotten why they were 

 FIG. 58. A parasite (Pimplacon- brought over to this COU ntry some 



quisitor} of the sncw-white linden ,. n/r r> 



^ forty years ago. Mr. Grote, in a paper 



from which we have already quoted, 



after discussing the great abundance of the measure worms in Brooklyn, 

 says further, "The advent of the English sparrow changed all this. 

 The naked brown larvae of subsignaria disappeared before them." 



In 1880, Mr. G. H. French of Carbondale, 111., bred five males and 

 seven females of a minute Hymenopterous parasite, Macrocentus irides- 

 cens, from two caterpillars, which he took to be Ennomos subsignaria, 

 found on an elm tree. We have not been fortunate enough to find 

 this parasite present in any of the caterpillars reared by us. We have, 

 however, bred one single specimen of a common parasite, Pimpla con- 

 quisitor (Fig. 58), from the pupae of the snow-white linden moth. Since 

 only the one specimen has been obtained from the scores of pupae we 

 have had, it will be seen that this parasite is not abundant enough 

 'yet to be of any great service as a check. Mr. Harris says that Chalcis 

 ovata, a small parasite, has also been reared from the pupae. 



It may well be that the great and wanton destruction of birds is 

 one cause of the abnormal abundance of this insect. If one bird is 

 so efficient in the control of this pest, as the evidence shows it to have. 



