THE PALMER-WORM 



Yjpsolophus pometellus Harris. 



Order Lepidoptera ; superfamily Tineina. 



WJiy are many injurious insects mncli more abundant and destruc- 

 tive in some years tlian at other times? That most insect pests do 

 liave these " ups " and " downs " in their lives, is a well-known fact ; 

 but often the question cannot be satisfactorily answered, and rarely 

 can one predict when any insect may appear in unusual numbers. 

 Doubtless variations in climatic conditions, and in the number of 

 their parasitic insect and fungous enemies, are the principal factors 

 whicli bring about these "up" and "down" periods in the lives of 

 injurious insects. Usually the army-worm is noticeably destructive 

 for only one season in the same locality, and many years may elapse 

 before it again attracts the notice of farmers. The tent-caterpillars 

 and canker-worms liave now been unusually abundant for several 

 years in New York, but sooner or later the " down " period will 

 come and the forest species especially may remain in obscurity for 

 ma!iy years, as it did before its present "up" period. 



We have prefaced this bulletin with these apparently irrelevant 

 remarks because the insect to be discussed is the most striking illus- 

 tration of the " ups " and " downs " of an insect's life with wliicli 

 we have met. Some of our great-grandfathers may have suffered 

 from its ravages in the latter part of the 18th century, then its 

 " down " period lasted until the orcharding days of our fathers 

 in the middle of the 19th century, and again the pest remained 

 in obscurity for nearly another half century, so that it was a new 

 and unfamiliar insect to most orchardists when it suddenly appeared 

 in great numbers the past season. 



Beginning about June 15th, 1900, and continuing for nearly two 

 weeks, our daily mail included two or three letters about the ravages 

 of a new caterpillar in apple orchards. As soon as specimens of 



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