May 19, 1921 hopkins: biocumatic zones 227 



and varieties and the prevention of the introduction of pests from 

 one to another part of the world. These, together with the results 

 relating to variations in equivalent days and to the variations of the 

 recorded from a constant thermal mean, are new and represent new 

 methods and principles. The preliminary prediction of minor bio- 

 climatic zones represented by the meteorological stations of the Brit- 

 ish Isles and Germany is perhaps one of the most important yet 

 attained from the study and application of the bjoclimatic law. The 

 close agreement between the zones and variations in days indicated 

 by this method, as compared with those indicated by the phenological 

 method for western Europe, together with the close agreement found 

 between the predicted zones for North America and the Merriam 

 life zones, are significant, not only in this agreement of results from 

 two quite different methods and as related to two continents, but in 

 opening a new field of research and practice of exceptional promise, 

 in scientific and economic results, as related to a wide range of human 

 interests. 



The general results of this study of an intercontinental problem 

 in bioclimatics should leave little or no reasonable doubt as to the 

 fact of, and prevailing responses represented by, the bioclimatic law. 

 Neither should there be any doubt as to its practical application to 

 almost any problem in any branch of natural science which involves 

 a consideration of the responses of living organisms and climatic 

 elements to continental, regional and local influences, or to problems 

 that require a measure of the relative intensity of the factors of var- 

 iations as related to periodical manifestations and geographical dis- 

 tributions. 



BIOCLIMATICS. — Bioclimatic zones of the continents; with proposed 

 designations and classification^ — Andrew D. Hopkins, Bureau of 

 Entomology. 



The Major Zones are the Frigid, Temperate and Tropical, desig- 

 nated as Majors I, II, and III. These majors are divided into Minor 

 Frigid, Minor Temperate, and Minor Tropical, and are designated by 

 Arabic numerals, as follows: 



I. Major Frigid Zone. — Arctic and Antarctic, and Alpine, with 

 Minor Frigid 1, 2, 3 and 4 from the poles and from higher to lower 

 altitudes. 



' In connection with the author's address at the joint meeting of the Academy and Bi- 

 ological Society (see the preceding article) these designations and classification of biocli- 

 matic zones for the continents of the world were suggested. (Received April 12, 1921.) 



