INTRODUCTION. v 



The method of distribution of species in the Atlantic and Pacific districts, as 

 already observed by me in various memoirs, is entirely different. In the Atlantic 

 district, a large number of sjfecies are distributed over a large extent of country ; 

 many species are of rare occurrence, and in passing over a distance of several 

 hundred miles, but small variation will be found in the species obtained. In the 

 Pacific district, a small number of species are confined to a small region of country; 

 most species occur in considerable numbers, and in travelling even one hundred 

 miles, it is found that the most abundant species are replaced by others, in many 

 instances very similar to them; these small centres of distribution can be limited 

 only after careful collections have been made at a great number of localities, and it 

 is to be hoped that this very interesting and important subject of investigation may 

 soon receive proper attention from the lovers of science on our Pacific shores. 



In the Central district, consisting, as it does to a very large extent, of deserts, 

 the distribution seems to be of a moderate number of species over a large extent of 

 country, with a considerable admixture of local species ; such at least seems to be 

 the result of observations in Kansas, Upper Texas, and Arizona. 



For the purpose of enabling these investigations to be carried on in future with 

 less labor, I have caused the catalogues of the present memoir to be printed sepa 

 rately; the small size of the catalogue of species from Eastern New Mexico, will 

 call attention to the necessity of procuring more material from that region; while 

 the asterisks affixed to the species which have occurred in both sub-provinces, will 

 give the results thus far obtained in geographical distribution.* 



For many years in the early history of entomology in the United States, the 

 Coleoptera of Kansas were as well known, and even more fully described than 

 those found in the Atlantic States. They form, indeed, the subject of one of the 

 earliest and most extensive of the valuable contributions to entomology made by 

 Say. 



Having, in the year 1845, made a journey along the Platte river to Fort Lara- 

 mie, thence near the base of the mountains to the Arkansas, returning by that 

 river and the Santa F6 road, I was enabled to follow nearly in the footsteps of Say, 

 and had the singular good fortune to recover nearly all the species described by 

 him, and of which the types had been destroyed to such an extent that scarcely an 

 authentic specimen remained. 



Of the species described by him, and not obtained by me from this region, I have 

 introduced those which remain unknown to me, marking them thus (fide Say) ; the 

 others I have excluded, as I possess them from Missouri, the locality in most 



* The student will also consult in reference to the Coleopterous fauna of the Central and Pacific- 

 districts : I. My report on the insects collected along parallel 47, in Pacific R. R. Explorations and 

 Surveys, vol. xi., which includes a list of the species found on the Pacific Slope, north of San Francisco; 

 an appendix to the same in Proceedings of the Academy of Natural Sciences of Philadelphia, October, 

 1859. 



2. Catalogue of Coleoptera of the region adjacent to the boundary line between the United States and 

 Mexico ; Journal of the Academy of Natural Sciences of Philadelphia, second series, vol. iv., No. 1. 



3. Catalogue of the Coleoptera of Fort Tejon, California ; Proceedings of the Academy of Natural 

 Sciences of Philadelphia, February, 1859. 



