266 KANSAS UNIVERSITY QUARTERLY. 



green, the males almost a salmon red. I have been told by people 

 from various parts of the state of the numbers of red crayfish which 

 they have seen after a heavy washing rain, and since, so far as I 

 know, this is the only very red species we have in this region, I 

 believe that careful collecting will show this to be one of our most 

 widely distributed species. 



Individuals of this species must exuviate in their burrows. I 

 have watched very carefully the ponds in which the females are 

 found in early spring but have never found a specimen which was 

 at all soft from exuviation. As noted above, in the spring females 

 are occasionally found in these ponds with a few young which are 

 old enough, or nearly old enough, to leave the parent. This 

 makes it seem altogether probable that those females without 

 young have lost them before or immediately upon taking to the 

 open water. In C. immiinis Hagen, the females exuviate in the 

 spring as soon as the young abandon them, but this would seem to 

 indicate that such is not the case with C. gracilis. 



In the fall of igoo there were many young crayfishes, which 

 seemed to be C. gracilis, in the ponds from about October 20 

 to November 20. They appeared in great numbers at about 

 the same time as C. ivimunis disappeared. I also noticed young 

 of this species early in the spring of 1900. So it appears that 

 young and adult C. gracilis appear in the ponds early in the spring, 

 and that the young again appear late in the fall, after other species 

 have gone to their burrows. 



These young crayfish which were from three-fourths to seven- 

 eights of an inch in length when they disappeared in November, 

 1900, appeared again about the first of March, 1901. They were 

 then taken in great numbers. A few days later the ponds froze 

 over but the animals were still to be found, apparently as plenti- 

 fully as ever, under a layer of ice about one inch thick. This 

 spring the old animals did not appear until after the young. The 

 young grew rapidly and by the first of May had attained a length of 

 from one to nearly one and a half inches. Many smaller animals 

 about five-eights of an inch in length are now — May 9, — found 

 in the ponds and ditches. These are probably the young of C. 

 gracilis which were still carried by the female as late as March 27. 



I might add that as compared with some other species, C- 

 immunis, for instance, the per centage of mutilation in this species 

 is very small. It is very seldom that one finds an individual with 

 one of the great claws wanting or showing any indication of having 

 been regenerated. 



