May 19, 1921 proceedings: biological society . 241 



which the waves travel in their course. The "fading" phenomena are 

 closelv associated with the strays or atmospheric disturbances which affect 

 all radio communications. This paper will be published in the Journal of 

 the Wasliingtoii Academy of Sciences. 



F. B. Littell: The variation of latitude and the constant of aberration 

 from four years' work with the photographic zenith tube at Washington. 



A brief account was given of the principles of the photographic zenith 

 tube devised by Dr. F. E. Ross. The average probable error of a single 

 latitude for the four years 1916-20 was ±0.089 second. A curve was shown 

 giving the path of the North Pole as deduced from a combination of the 

 results of the Washington observations with the results of observations 

 made at Greenwich with the Cookson photographic floating zenith telescope. 



A value for the constant of aberration of 20.454 =t O.OOS second was 

 deduced from the observations, and curves showing the Kumiro or 2;-term 

 for the years 1916 and 1917 were shown. An analysis of the meteorological 

 conditions showed that the s-term could not be accounted for by the baro- 

 metric gradients. 



This paper will appear in full in the Astronomical Journal. 



Dr. R. S. Woodward characterized the subject as most important; and 

 regretted that there was not time for its full discussion. 



H. H. Kimball, Recording Secretary. 



BIOLOGICAL SOCIETY 

 617th meeting 



The 617th regular (41st annual) meeting of the Biological vSociety of 

 Washington was held in the lecture hall of the Cosmos Club on December 

 11, 1920, with President A. D. Hopkins in the chair and 2S persons present. 



It was announced that on May 15, 1920, the resignations of N. Dear- 

 born as Treasurer and A. Wetmore as Corresponding Secretary were re- 

 ceived, and that F. C. Lincoln became the new Treasurer and T. E. Snyder 

 the new Corresponding Secretary. 



Reports of officers and committees were received, and officers and mem- 

 bers of the council were elected, as follows: 



President, N. Hollister; Vice-Presidents, A. S. Hitchcock, J. W. Gid- 

 LEY, S. A. RoHW^ER, H. C. Oberholser; Recording Secretary, A. A. Doo- 

 LiTTLE; Corresponding Secretary, T. E. Snyder; Treasurer, F. C. Lincoln; 

 Members of the Council, Wm. Palmer, E. A. Goldman, H. H. T. Jackson, 

 R. E. Coker, R. W. Williams. 



61STH meeting 



The 61Sth meeting of the Society was held in the lecture room of the 

 Cosmos Club at 8.10 p.m. on January 8, 1921. President N. Hollister 

 called the meeting to order with 62 persons present. On recommendation 

 of the Council, Mr. E. G. Runyan was elected to membership. 



The President announced the following committees: Committee on Pub- 

 lications, C. W. Richmond (Chairman), J. H. Riley, T. E. Snyder, F. C. 

 Lincoln. Committee on Communications, S. A. Rohwer (Chairman), C. E. 



ChAMBLISS, J. S. GUTSELL. 



Informal communications 

 J. M. Aldrich exhibited dried specimens of caterpillars of Coloradia pan- 

 dora Blake, which are used as food by Indians in the vicinity of Mono Lake, 

 California. The species has a two-year cycle. Feeding on the Jeffrey pine 



