PREFATORY NOTE 



The present memoir, entitled "A Synopsis of the Acrididse of North 

 America," by Professor Thomas, is offered for publication at this time with 

 the belief that it is a substantial contribution to Natural History. It is one 

 of the results of the author's connection with the Survey for the past four 

 years. It forms the first part of Vol. V, which is intended to include only 

 special papers on subjects connected with the recent Zoology and Botany of 

 the Survey. The catalogues, with brief descriptions of the new species that 

 are collected from year to year, will appear in the annual reports, while the 

 more elaborate descriptions, with the illustrations of the new or little-known 

 species, will be included in this volume. The Fishes and Reptiles will be 

 elaborated by Professor Cope, the Botany by Professor Porter, Hemiptera 

 by P. R. Uhler, Coleoptera by Dr. Horn, Birds by Dr. Coues, and Mammals 

 by Professor Gill. 



We trust that this array of names of men so eminent in these special 

 departments will be a sufficient guarantee for the value of this work. 



I beg to extend to all these gentlemen my cordial thanks for their kind 

 co-operation. 



F. V. HAYDEN, 



United States Geologist. 



Office U. S. Geological Survey of Teuritories, 



January 10, 1873. 



