The Crawi'ishes ok Western Pennsylvania. 395 



Cambarus caroliiiiis is, as has been first reported by Faxon, a bur- 

 rowing species, and makes holes in swampy and springy ground on the 

 mountains. Favorite localities are swampy meadows on the top of 

 the hills or on the hillsides, often apparently dry at the surface, but 

 containing at the de[)th of one to two feet a supply of fresh spring 

 water, generally with a substratum of stiff clay. The holes of this 

 species are very complex, having very often several openings, each of 

 which is crowned by a more or less regular "mud-chimney." At 

 Ohiopyle, I have dug them out of holes, two or three feet deep, the 

 holes forming, at this depth, a very intricate system of caverns and 

 tunnels, branching off more or less horizontally in various directions. 

 In certain parts of Somerset county, and in Garrett county, Maryland, 

 this species is a real pest, seriously interfering with farming on ac- 

 count of its burrows and mud chimneys. 



Faxon gives 62 mm. as the maximum size for this species. I have a 

 male of the first form from Dunbar, Fayette county, which is 63.5 

 mm. long, and a female from Ohiopyle, Fayette county, which meas- 

 ures 80 mm. There is no doubt that adult males also attain a similar 

 size, but it is hard to take them on account of the depth to which the 

 holes of old individuals go down. 



3. Cambarus mononcaeensis species nova. The Blue Crawfish. 



Diagnosis. — A species belonging to the third group (C /nirtoni), 

 being most closely allied to C. caroliuus, but differing in the following 

 characters : 



1. Rostrum narrower, a little variable in shape, but generally with 

 margins more convergent, and the lateral angle at the base of the 

 acumen less well defined. 



2. Armature of chekne different. Outer margin of hand not ser- 

 rated, being swollen and evenly rounded, the pits (punctuations) 

 never forming a regular longitudinal row on the edge. Carpopodite 

 with more than one spine on the inner side. Generally, one spine is 

 the largest (the one corresponding to the spine of C. caroliuus^, but 

 there are always several other small spines or spine-like tubercles. 

 Lower side of meropodite only on the inner edge with a row of spines, 

 the outer edge is smooth, with a single tubercle at its distal end. 



3. Color blue. It is most brilliant on the anterior part of the cara- 

 pace and on the chelae, being of a deep ultramarine hue, shading to 

 sky-blue on the sides. Distal part of the fingers of chelae orange or 



