62 Bulletin No. 159 



common, and so large that it could be seen with the naked 

 eye by holding a jar up to the light. A stalked species was 

 observed attached to the foot of one of the bugs known as 

 water striders and is represented in one of my figures 

 (Fig. 24). 



CRUSTACEA (CRAWFISHES, ETC.). 



The best known crustacean of the fresh waters of this 

 country are known everywhere as crawfishes, sometimes 

 simply as craws, and among college men, as crayfishes, this 

 British word having been imported with laboratory manuals. 

 All of the species of the Eastern United States belong to the 

 genus Cambarus, of which there are about sixty known, 

 eleven of them, possibly a few more, occurring in Kentucky. 

 They are all much alike in general structure, being provided 

 with a pair of strong forceps, on the forward pair of walk- 

 ing legs, and at the hind end of the body with a fin com- 

 posed partly of the flattened last segment and partly of the 

 hindmost expanded and branched appendages. With this 

 caudal fin they swim swiftly backward, as everybody knows, 

 a method of progression with the advantage of keeping the 

 strong claws and eyes directed toward pursuing enemies, 

 but with some disadvantages also, as when one of them 

 swims thus into the mouth of a black bass. They are in 

 fact excellent fish bait. They are common in the streams 

 about Pineville, and though my attention was concentrated 

 on the search for Simulium, two species of crawfish, Cam- 

 barus bartoni and C putnami were collected in the Cumber- 

 land River, and a third, apparently C. girardianus, was col- 

 lected in the rapids near the Roark cottage at Gary. 



The crawfishes are of special interest as inhabitants of 

 these waters because of their value for fish food. But their 

 great abundance in situations frequented by Simulium may 

 give them an important relation to the welfare of the latter. 

 As a rule, I believe they are more vegetarian than predatory, 

 but while feeding upon plants at all times, some of them un- 

 doubtedly seize and devour animals coming within their 

 reach, when prowling about under rocks, and they are 



