HARRIS : CRAYFISHES GENUS CAMBARUS. 61 



broader surfaces of body, as sides of carapace, inner faces of an- 

 terior abdominal epimera, and external face of tail fin. Adults 

 found attached almost anywhere on exterior of crayfish, but 

 more especially on the tergal surfaces. On C. bartonii, Watauga 

 county, North Carolina. 



B. instabilis Moore, sp. nov. Cocoons usually attached to 

 palmar surface of propodite of great chelie. Animals largely 

 restricted in distribution to the same segments of the limb ; 

 usually to be found in numbers clustered at the base of the 

 pinchers, to which position the form of the body particularly 

 adapts them ; frequently wandering to other parts of the same 

 limb, or even to the following pairs of ambulatory limbs. 

 Watauga county, North Carolina, and Delaware county, Penn- 

 sylvania. 



B. philadelphica Leidy. According to Leidy ('52), this spe- 

 cies is found frequently in numbers from one to several dozen 

 upon any part of the exterior of the body of A. bartonii, but 

 more especially upon the interior surface and the branchiae, 

 but Moore ('93) never found it inhabiting the branchial cham- 

 ber, but principally the sternal surface of the entire body, among 

 the bases of the appendages. Cocoons attached to abdominal 

 sternites, but more frequently to the seta? of pleopods ; found 

 principally in summer, but not entirely absent at any season. 

 Philadelphia, Pa., and Watauga county. North Carolina. 



Bouvier ('97) states that of the twenty specimens of C. 

 digueti received four were attacked by Temnocephala and two 

 carried a large number of BranchiobdeUa. 



THE COLORS OF CAMBARUS. 



Owing largely to the necessary condition of our museum ma- 

 terial, very little is known of the colors of our crayfishes. In 

 the systematic literature there are a few references to this char- 

 acteristic in the descriptions of the species, but with these w^e 

 are not concerned here. 



Kent ('01) has recently published observations, for the most 

 part on C. immunis, with some work on C. propinquus, C. 

 bartonii, and C. diogenes, in which he concludes that in nearly 

 all cases the color of the animals closely resembles that of the 

 environment, being blue in color in a pond where the bottom 

 was of blue clay, black where there was a muddy, black bot- 



