6o8 THE AMERICAN NATURALIST. [Vol. XXXVII. 



ately after they quit the burrows in the spring. In southern 

 Kansas, C. simulans has been taken from burrows, with eggs 

 apparently recently laid, late in August, and in New Mexico, 

 with the swimmerets loaded with eggs, in May. In C. immnnis 

 the females are found with eggs in stagnant ponds in the fall ; 

 they pass the winter in burrows and appear again in ponds, 

 where the process of hatching is completed, in the early spring 

 — about March 21st. C. argillicola has been reported with 

 young as early as April 2nd. C. neglectus was found with eggs 

 and young in the cold water at the mouth of a large limestone 

 cave in the Ozarks early in June, and since those taken at the 

 same time in various other places in the neighborhood had 

 neither eggs nor young, the lateness of the date may be attrib- 

 uted to the retarding effect of the low temperature upon the 

 hatching of the eggs. In another locality C. neglectus (?) was 

 taken with eggs April 13th. In C. virilis the females are found 

 with eggs in the spring, but not during the winter. 



Of the above species C. diogcues and C. gracilis are preemi- 

 nently burrowing forms, C. argillicola is a burrower, C. simulans 

 burrows extensively as does also C. immnnis, and C. virilis some- 

 times resorts to the habit. C. neglectus seems to be found prin- 

 cipally, in clear rocky streams. In regard to the burrowing spe- 

 cies it has been suggested that the burrow is designed as a retreat 

 while the eggs are being hatched, but this is not very likely, 

 although the eggs may undergo a very large part of their develop- 

 ment in the burrow. 



Observations on the habits of the young crayfish are few. 

 Two suggestive ones are that in C. diogencs the neatest chimneys 

 are those constructed by the smallest individuals and that the 

 young of C. gracilis are the first to appear in the stagnant ponds 

 which are frequented by this species in early spring and are also 

 found there in the late summer after other forms, C. immnnis, 

 C. virilis, and the adults of C. gracilis, have gone into their bur- 



