INSECTS AFFFXTING PARK AND WOODLAND TREES I 33 



of this insect, and the extensive defoliations which occurred at the time 

 aroused the people to the necessity of fighting the pest. This was done so 

 effectively that very little trouble with this caterpillar was reported in 1899. 



Early history. This species was regarded in earlier years as a serious 

 enemy to appletrees in Ontario, for Rev. C. J. S. Bethune, writing in 1871. 

 stated that it was a serious pest and that in the Western -States it had 

 defoliated some of the orchards, and even attacked the fruit. The late Dr 

 Lintner, in his second report, records several instances of severe injury to 

 fruit trees by this species. Serious depredations have also been reported by 

 Professor Lowe, entomologist of the State Agricultural Experiment Station. 

 He received many comijlaints in 1895, specially from Yates and Ontario 

 counties, where the caterpillars not only devoured foliage, but attacked 

 the fruit. He states in his report that one fruit grower estimated the loss 

 on his apple crop at 25 percent. 



A city pest. This insect is widely distributed over the country, but it 

 is one of those forms which are much more destructive in the cities and 

 towns than in the country. The cause for this is probably found largely in 

 the protection- afforded by the English sparrow. It not only fails to feed 

 on this caterpillar but drives away many native birds that would. I )r J. L. 

 Le Conte has placed on record an interesting instance of the effect this bird 

 may have on our local fauna. He states that the English sparrow was 

 imported for the purpose of keeping in check the snow white linden moth, 

 Ennomos subsignarius Hiibn., and that in Philadelphia, after the 

 sparrows had destroyed the Ennomos larvae, the white marked tussock 

 moth caterpillars found abundant food, and being unmolested by the spar- 

 row on account of their irritating hairs, they soon became even worse pests 

 than the other species. 



Other forms of Hemerocampa. There are several other species in the 

 country belonging to this genus, one of which, H. d ,- f i n i t a Packard, has 

 frequently been confused with H. leucostigma. As an aid to the 

 ready identification of these interesting larvae, the following table by Dr 

 Dyar is reproduced. 



