8 NORTH AMERICAN ACRIDIID^. 



the shape of a classification of locust habitats and societies and an 

 explanation of brachypterism in Orthoptera. 



Acknowledgments are due, primarily, to the Carnegie Institu- 

 tion for the means wherewith to pursue this investigation ; secondly, 

 to Mr. Samuel Henshaw, of the Museum of Comparative Zoology, 

 for the opportunity to study critically the Scudder collection, with- 

 out access to which certainty of determination would in many cases 

 have been impossible ; and finally, to numerous fellow-scientists, 

 travelers, and observers, for their cordial interest and assistance in 

 various ways. Among these I desire epecially to mention Mr. J. H. 

 Emerton, of Boston; Messrs. Sherman and Brimley Bros., of Raleigh, 

 and Boynton, of Biltmore, North Carolina, for information regarding 

 conditions and localities ; and Messrs. Fernald and Greenman, of 

 Cambridge, Massachusetts, for determination of plant specimens. 



BIOLOGICAL IMPORTANCE OF THE SOUTHEASTERN 

 UNITED STATES. 



The chief biological importance of the Southeastern United 

 States, comprising Virginia, North and South Carolina, Georgia, 

 Florida, Alabama, eastern Tennessee, and West Virginia, is con- 

 nected with two facts : First, this region served during the Glacial 

 Epoch as a refuge for boreal forms of life which had been pushed 

 southward by the climatal conditions of the Ice Age, and at the 

 close of that period it became the center of dispersal whence these 

 forms were able to restock the opening country at the north. 

 Second, during this later period its lowland plains served, and 

 probably continue to serve, as a highway of dispersal for austral 

 forms entering the country from the south and southwest, many 

 of which have penetrated far into the heavily glaciated region of 

 the Northern States. 



Notwithstanding its great biological importance, this region has 

 not received the attention scientifically which it deserves, save 

 with reference to certain groups and in certain sections, such, for 

 instance, as peninsular Florida, which, owing to its southern posi- 

 tion and consequent attractiveness, both biologically and as a winter 

 resort, has received considerable attention and study. As a matter 

 of fact, the Acridian fauna of no area in the United States of equal 

 size and biological importance was so little known at the beginning 

 of the year. For this reason it was decided to spend the summer in 

 a general reconaissance trip through the region, securing as many 

 facts relative to systematic facies, geographical, zonal, and seasonal 

 distribution, habitats and environmental conditions, life histories, etc., 

 as possible. 



