142 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 11, NO. () 



A table of altitude and latitude limit constants was prepared from which 

 the altitude limits were computed for the several stations and when these 

 were compared with the records they were found to closely approximate them. 

 This served as a basis for making maps of the distribution of the generations 

 and examples of such maps were exhibited. 



It was concluded that, if the computed or forecasted dates for the hatching 

 of the eggs of the several generations, the dates for the falling of the apple 

 petals, the thermal means and the altitude limits for the several generations, 

 agreed so closely with the records from six widely separated stations, similar 

 forecasts from the same tables for any place within the United States should 

 come close enough to the actual date or altitude limit for all practical pur- 

 poses. It appears safe to assume, therefore, that with records from a few 

 representative places in a State or the United States fairly reliable information 

 on these and similar problems in entomology can be forecasted for any place 

 and thus avoid a large amount of local investigation. 



A. T. Speare: The relation of Fungi to insects. 



It was pointed out that fungi are associated with insects in several ways. 

 (1) An association in which insects prey upon fungi. (2) The commensalistic 

 association. (3) The symbiotic relationship. (4) An association in which 

 fungi are parasites upon insects. Examples of the first three types were 

 briefly considered. Examples of the fourth type of fungi that live as parasites 

 upon insects were considered in some detail, particularly with reference to 

 the pathogenic forms. Lantern slides showing many rare exotic entomo- 

 genous fungi were shown. 



33 1st meeting 



The 331st meeting was held on May G, 1920, at the Cosmos Club, with 

 President Walton in the chair and 34 members and 8 visitors present. Dr. 

 Franz Schrader was elected to membership. 



Program 

 J. M. Aldrich: Bot Hies and their biology. 



Dr. Aldrich summarized what is known of the host relations both as to 

 the species of the host, the oviposition habits and methods of ingress into the 

 body of the host, and the subsequent development of the immature stages. 



J. J. Davis: The Japanese beetle and operations under way for its control. 



This was a statement concerning the work under way at River ton, N. J., 

 looking to the control of this introduced pest. Many photographs of control 

 operations were exhibited. 



Dr. F. KoLPiN Ravn, Professor of Plant Pathology in the Royal College 

 of Agriculture at Copenhagen, Denmark, was invited by the President to 

 address the vSociety. Dr. Ravn spoke on the desirability of cooperation be- 

 tween entomologists and plant pathologists. He brought out the close 

 relationship between insects and the organisms causing diseases of plants, 

 citing some very striking examples of the interdependence between the two 

 factors. He expressed the opinion that the well-trained plant pathologist 

 should have a good knowledge of zoology, systematic botany (including 

 mycology and bacteriology), as well as plant physiology, while specializing 

 in one subject or another. This he thought necessary to enable the pathol- 

 ogist to determine at once all of the more common diseases and injuries and 

 to give advice as to remedial measures. 



