OKTMANN: the CRAWFISHES OF THE STATE OF PENNSYLVANIA 371 



The avnidus ventndi.s of the female has the general shape of that of (.'. proj)in- 

 quas, but the depression in the middle is well marked, and the anterior part has 

 two distinct, subconical tubercles. The posterior part is also elevated into a flat 

 and low tubercle. These tubercles are less distinct in young specimens, but always 

 well developed in females of medium and large size. 



Size. — Hagen gives the length as 3.5 in. = 89 mm. The largest individual at 

 hand is a female from Pucketta Creek, Allegheny County (Atkinson coll.), wliich 

 measures 93 mm. in length. Tlie largest male of the first form is from the Ohio 

 River at Neville Island, Allegheny Co., which is 8G mm. in length. Individuals 

 over 80 mm. in length are not rare in the larger rivers. 



Colori) (Plate A, Figs. 1 and 2). — The colors of this species are identical with those 

 of C. prfqnnqtms. In fresh specimens the general ground color is light olive-green 

 (Ridgway, 1886, X, 18), with darker spots in young specimens ; in older individuals 

 it is rather taivny-olive (III. 17). On the branchial region there is an oblique band of 

 cream-color (\l, 20), edged by olive-green near the margin of the carapace, which is 

 again cream-color. This cream-color in very brightly colored specimens sometimes 

 becomes primrose-yellow (VI, 13). On the anterior margin of the carapace below the 

 eyes there is a spot which may be rufous (II, 7), ocliraceous-rufous (V, 5), edged with 

 sulphur-ijelloxv (VI, 14), ochre-yellow (V, 9), or primrose-yellow (VI, 13). The abdomen 

 is olive-green or lawny-olive, shading into chestnut (IV, 9) on the anterior margins of 

 the segments. There are one (sometimes two) median and two lateral rows of dark 

 olive-green patches. The chelte are light olive-green, shading distally into olive-yellow 

 (VI, 16). The finger-tips are orange-buf (\'I, 22), orange [Xl, 3), or raw sienna 

 (V, 2), followed by a pale, and a dark green, sometimes almost black band. Tlie 

 latter is not alwaj's present. The upper surface of the hand at tlie base of the dac- 

 tylopodito has two (rarely one) rufous or ochraceous-rufoas (V, 5) articular tubercles. 

 The tubercles of the hand are huff-yellow (VI, 19) or huff (V, 13). The articular 

 membranes of the hand are wine-purple (VIII, 15). The legs are olirr-yellow (VI, 

 16) and whitish, with olive-green on upper edges. 



The above colors fade in old specimens, and are often obscuivtl l)y blackish or 

 brownish coats oi'dirt. .\ variety with the chehe and anterior parts of the carapace 

 of a pale dirty liluish color was repeatedly observed in tlie Alleghany River at 

 Sandy Creek and Twelve Mile Island, liut only old specimens of this form were 

 found. Young specimens generally vary more toward green, old ones toward tawny 

 or brown. 



The color of the newly laid eggs ranges from sage-green (X, 15) to dark olive- 

 green (X, 18), or often to almost bku:k. When somewhat advanced in development, 



