3?6 Report of the Entomologists of the 



natural checks. 



Insects that live so much exposed while in the caterpillar stage 

 as does the apple tree tent caterpillar fall an easy prey to many 

 natural enemies which greatly lessen their numbers. The natural 

 checks upon this insect may be classified under 5 heads, as follows: 

 Climatic changes, birds, predaceous insects, parasitic insects and 

 parasitic diseases. 



Climatic changes. — The caterpillars are most susceptible to 

 these changes just after hatching or before they have become well 

 established in the nest. A cold wind and rain storm at this time 

 may kill great numbers of them. 



Birds. — Birds form one of the most important natural checks 

 to many species of noxious insects. But unfortunately many of 

 the birds which depend largely upon insects for food are being 

 rapidly killed off, thus depriving the farmer of some of his most 

 valuable allies in his conflict with his numerous insect enemies. 



The following birds are known to feed upon the apple tree tent 

 caterpillar: The yellow-billed and the black-billed cuckoos, black- 

 capped chicadee, Baltimore oriole, red-eyed vireo and wren. 

 Xeariy all of these have been observed in and about Geneva. 

 Of these the yellow-billed and the black-billed cuckoos and black- 

 capped chickadee are probably the most important. The former 

 feeds readily upon the caterpillars, while the latter feeds upon the 

 eggs and young caterpillars. According to Forbush, as quoted by 

 Weed, 11 the crow, chipping sparrow and yellow warbler also feed 

 upon the caterpillars. It is probable that the warbling vireo may 

 also be added to this list as Mr. W. P. Wheeler states that he re- 

 cently saw one enter a nest of the caterpillars, remain for several 

 minutes and give other evidence of feeding upon the young cater- 

 pillars. Further observation will undoubtedly add many species 

 to this list. The writer will be especially glad of any informa- 

 tion relating to the birds which prey upon noxious insects. 



n N. H. Coll. Agrl. Expt. Sta. Bui. 38, p. 55. 



