59 



few 3'eai's later disappear. Tbe}- are de.stro3'ed by parasites or by 

 climatic conditions and soon become rare species. Tbis happened in 

 the case of the pine insect, Avhich was scarce!}' heard of before, and 

 was one of the rarest insects in collections until it suddenly occurred 

 in 1891 in such enormous numbers as to destro}' millions of dollars 

 worth of timber, but now it is practically extinct. Not a single living 

 specimen has been found since the fall of 1892. Professor Johnson's 

 paper shows the great importance of the work he has undertaken, and 

 his experience will be of inestimable value in dealing with future out- 

 breaks of the pea louse. He thought the farmers of Mar}' land would 

 make a great mistake by changing their locations for growing peas 

 until perhaps a year has elapsed, because if the rule follows in regard 

 to sudden invasions by indigenous insects they will soon disappear or 

 become rare. 



Mr. Johnson said he was greatly obliged to Mr. Hopkins for his 

 opinion, but there is so much money at stake that the growers could 

 not let the matter rest awaiting nature's relief. He believed fungous 

 diseases, especially Empusa ajpTddh^ is one of the factors which will 

 bring about the temporary disappearance of the pest. 



Mr. Galloway said the point in regard to the appearance and dis- 

 appearance of forms holds good in fungous attacks also, the most strik- 

 ing example being the potato blight. The same holds good in the 

 passing of the Russian thistle. These things come and go and come 

 again, and the principle holds good with fungous diseases as well as 

 with insects. 



The next paper, by Mr. Galloway, was entitled: 



PROGRESS IN THE TREATMENT OF PLANT DISEASES IN THE 



UNITED STATES. 



By B. T. Galloway, Washington, D. C. 



[Printed in the Yearbook of the Department of Agriculture foi' 1900.] 



The next paper, by Mr. Webster, was entitled: 



METEOROLOGICAL INFLUENCES ON THE HESSIAN FLY. 



By F. M. Webster, Wooster, Ohio. 

 [Withdrawn for pubUcation elsewhere.] 



The meeting then adjourned to Central Park to inspect Mr. South- 

 wick's spraying outfit. 



AFTERNOON SESSION, JUNE 23. 



Owing to the large number of papers to be read, it was resolved 

 that each author be allowed ten minutes in which to present an abstract 

 of his paper, and that all discussions be postponed until the papers had 

 been presented. 



