■»• < . 



CONTENTS. 



PAGE. 



Table op Contents iii 



List op Oppicers v 



List op Members. Revised to December 31, 1912 vi 



1. Patrons., 



2. Honorary Members. 



3. Active Members. 



Abstract of History xviii 



Record. January 1, to December 31, 1912 xxii 



Papers Published, January 1, to December 31, 1912 : 



1. Henry Ellsworth Ewing. — The Origin and Sig- 



nificance of Parasitism in the Acarina. — 

 Plates I-VII.— Issued June 18, 1912. ....... 1 



2. Geo. A. Lindsay. — The Annual Rainfall and Tem- 



perature of the United States. — Plate VIII. — 

 Issued June 19, 1912 71 



3. Francis E. Nipher. — The Nature of Electrical 



Discharge — Positive Column Effects in a 

 Metal Conductor. — Plate IX. — Issued July 

 3, 1912 79 



4. Title Page. Prefatory Matter and Index of 



Vol. XXI. Record January 1, to December 

 ■ 31, 1912.— Plate A.— Issued May 5, 1913. 



List op Authors 89 



General Index 90 



Index to Genera 93 





