OF WASHINGTON, VOLUME XIII, 1911. 117 



at a station on the campus of the university, nor did those of 

 the university agree with those at a station on the mesa, 

 which is about 50 feet above the campus. This shows the diffi- 

 culty the Weather Bureau would have if they endeavored to 

 give all the data necessary in a given locality. 



Mr. Johnson spoke of the difficulty he had experienced in 

 trying to correlate the emergence of the grape root-worm with 

 plant conditions. There is great variation, a striking one 

 having occurred in the spring of 1908, which was unusually 

 cold but eventually warmed up in June. The cold May re- 

 tarded pupation for about a month. Some individuals of the 

 codling moth or plum curculio may hibernate in warmer 

 places than others, and will naturally mature more rapidly. 



Professor Webster said Mr. Reeves has found differences of 

 emergence on the north and south slopes of hills. 



Mr. Ely asked what attention has been paid to soil temper- 

 atures. 



Mr. Pierce replied that very little had been done in this re- 

 spect, but that it would be necessary in insect-development 

 studies to obtain accurate records of the temperature at vari- 

 ous depths in relation to soil moisture, texture, etc. ; that the 

 soil temperature in Texas often ran 40 higher than the air, ac- 

 cording to its color and consistency. 



Dr. Hopkins said this was of enormous importance; that he 

 had studied the relation of exposures and other factors gov- 

 erning forest insects, but that other influences must be con- 

 sidered for insects living part of their time underground. 



Mr. Pierce closed the discussion by stating that the pur- 

 pose of his paper was to show that records and laws of devel- 

 opment should consider air temperature and humidity; soil 

 temperature, humidity, and texture; food moisture and tex- 

 ture; sex; phenology; and probably many other factors. 



-The last paper of the program, "A Note on the Occur- 

 rence of Chrvsoinvza dcnuindata Fabr.," by C. N. Ainslie, 

 was read by the Secretary. 



