318 JOHN HAMILTON, M. D. 



extreme southwestern Pennsylvania, JNIaryland and West Virginia, 

 their uniou forming the Ohio, which has a northwestwardly flow of 

 twenty-five miles before trending to the southwest. 



The Allegheny drams the southern part of western New York 

 and the western slope of the northern Alleghanies, while their cen- 

 tral and southern portions in Pennsylvania, Maryland and West 

 Virginia are drained by the Monongahela ami its tributaries. 



The surrounding country is mainly broken and hilly, indented in 

 every direction by deep valleys, often having very abrupt sides, and 

 through which flow brooks or larger streams. The country is of a 

 similar character eastwai'd to the Alleghanies, of which this region 

 may be considered part of the foot-hills. Thus, as might be expected 

 from the topography outlined, s[)ecies from the north, from the south 

 and from the mountains all commingle here, as well as the forms 

 which come eastward through the basin of the Ohio. 



Only a very small territory has been collected over ; more than 

 nineteen hundred of the species listed were taken on the right or 

 western bank of the Allegheny on a strip of ground about ten miles 

 long measuring from the present eastern l)oundary of Alleghany, 

 and one and one-fourth miles wide, and even this interrupted by five 

 populous boroughs— Millvale, Etna, Sharpsburgh, Aspinwall and 

 Holioken. No collecting was done in Pittsburgh between the Alle- 

 gheny and Monongahela. Messrs. William, Henry and Edward 

 Klages, collected extensively on the left or western side of the Mo- 

 nongahela, as was done b}' myself to a less extent, but less than one 

 dozen species occurred there which were not eventually taken in the 

 Allegheny district. Species however rare in one region, were often 

 abundant in the other, and vice versa. 



This list must, by no means, be considered as exhaustive of the 

 Coleoptera fauna of this locality. The Scydmsenidse, Trichopter- 

 ygidte, Pselaphidte, Aleocharini, Dytiscidas, Cryptophagidre, Lath- 

 ridiidai, etc., have scarcely been touched. 



The future collector must not expect to take on the territory indi- 

 cated all of these species ; the ruthless hand of improvement is 

 rapidly destroying the primitive features of the locality, and even 

 now many of those must be sought elsewhere that were abundant 

 twenty years ago. 



While the foregoing remarks apply to a very restricted locality it 

 must not be inferred that the species occurring there are e(]ually 

 restricted, as in fact they are the conunon Coleoptera of southwestern 



