CONTROL OF INSECT PESTS McATEE 429 



of the latter instances was observed by Mr. Frank N. Wallace, 

 State entomologist. 



In the case of another large moth — namely, Samia cecrojna of the 

 family Saturniidte — the late Prof. F. M. Webster recorded the 

 destruction of all but two of the cocoons of this species in a grove 

 in Illinois by hairy woodpeckers. Dr. John D. Tothill, who has 

 published so much interesting information on natural enemies of 

 insects, concludes that in his region (Nova Scotia) nearly three- 

 fourths of the cecropia caterpillars are eaten by orioles, robins, 

 and other birds, and about 85 per cent of the pupae are destroyed 

 by woodpeckers. When M. Leopold Trouvelot was experimenting 

 with the so-called American silkworm {Telea polyphemus) he found 

 birds to be the most formidable enemies of the caterpillars, and 

 he says : " It is probable that ninety-five out of a hundred worms 

 become the prey of these feathered insect hunters."-^ In one case, 

 to test the birds, he jjlaced 2,000 of the larvae on a tree near his door, 

 and in a few days the birds had eaten all of them. 



Excessively hairy larvae are characteristic of the family Arctiidae, 

 but at least one of them, the fall webworm {Hyphatitrla textor), 

 is freely eaten by birds. Dr. C. Gordon Hevv^itt informs us that, 

 " The study of the natural control of the fall webworm was extended 

 to Nova Scotia in 1916, and it is interesting to record that of the 

 different factors operating in the reduction of this insect the red- 

 eyed vireo, Vireosylva olivacea L., appears to be the most important. 

 It was estimated that about 40 per cent of the larvae had been 

 destroyed in the webs by this bird at the five observation points." -* 



The observations referred to are those of Doctor Tothill, who 

 credits birds with percentages of destruction of the broods, varying 

 in different years, from 11.4 per cent to 89.5 per cent. In 1912, 

 when the insect was fairly plentiful, a reduction in numbers was 

 brought about chiefly by parasites. In succeeding years the para- 

 sites gradually died out as the insect became rare, and control was 

 maintained almost exclusively by birds.-^ 



While it may not be well known that hairy caterpillars are eaten 

 so freely by birds, it is common knowledge that cutworms are favorite 

 meat. Cases of local control of cutworms by birds must be of fre- 

 quent occurrence. However, only the following cases seem to be on 

 record: Three instances relating to unidentified cutworms — namely, 

 control of ground cutworms in Massachusetts by starlings, and in 

 Utah by meadowlarks, and of climbing cutworms in California by 

 crows— and the following relating to identified forms. Prof. J. R. 



2»Am. Nat. I, No. 2, April, 1867, p. 89. 



-' Rep. Dominion Ent., 1917, p. 8. 



2E Proc. Eut. Soo. Nova Scotia, 1918, pp. 10-14. 



