6 THE GYPSY MOTH. 



was introduced from France, our harsher climate may have 

 destroyed many of the smaller caterpillars before they had 

 attained strength enough to resist exposure to its sudden 

 changes. A warm period early in the season, followed by a 

 cold storm or severe frost, sometimes destroys many of the 

 young caterpillars. They are first hatched by the unsea- 

 sonable warmth, and then killed by the cold immediately 

 following. 



2. Isolation, with all its attendant perils. The isolation 

 of the species and its small numbers rendered it peculiarly 

 sensitive to the attacks of new enemies which surrounded it. 

 Parasitic and predaceous insects were no doubt plentiful 

 then, as they are to-day. The topography of the locality 

 and the vegetation of the neighborhood were such as to ren- 

 der it specially attractive as a breeding ground for insect- 

 eating birds. Myrtle Street was then flanked by gardens 

 and orchards, and nearly surrounded by woodland and bushy 

 pasture. Not far to the east is a small swamp and stream, 

 and the whole locality lies near the marshy banks of the 

 Mystic Kiver. Many of the birds which frequent such places 

 feed on the gypsy moth in one or more of its forms wher- 

 ever it is found. It is related in Samuels's " Birds of New 

 England," published in 1870, that Mr. Trouvelot, who was 

 then engaged in rearing silk-worms, placed two thousand of 

 them on a small oak in front of his house, and that in a few 

 days they were all eaten by robins and catbirds. He had a 

 large area of woodland fenced in and covered with netting 

 to protect his silk-worms. The birds came from all quarters 

 to feed on the worms, breaking through the netting, so 

 that he was obliged to shoot them in defence of his " infant 

 industry."* Mr. Trouvelot, in describing his work on the 

 American silk- worm {Telea polyphemus) , says that it is 

 probable that ninety-five out of a hundred worms become 

 the prey of birds, f 



At that time the cuckoos, blue-jays, orioles, vireos, cat- 

 birds, bluebirds and warblers which are known to feed upon 

 the caterpillars were also abundant in that locality during 

 the season when the caterpillars were feeding. The inroads 



* Birds of New England, page 156, t American Naturalist, Vol. I., page 89. 



