No. 503] CAMBARUS BARTONIUS BARTON1 711 



The water was changed daily and oftener at feeding 

 time, during the entire winter, and record kept of the 

 activities of the crawfish. It was not until spring, how- 

 ever, that night and day observations were made. 



During the fall and winter, up to February 1, frequent 

 cases of copulation were observed. Contrary to Dear- 

 born's statement, '00, I found that the males do not know 

 the females and that males repeatedly grasp other males, 

 and sometimes, in spite of their frantic struggles, turn 

 them over and attempt to copulate with them. The dif- 

 ference in behavior in the case of the male, when thus 

 grasped, is that he continues to resist violently at inter- 

 vals, until released, while the female, as soon as grasped 

 firmly, ceases to struggle, and lies passive. 



Another interesting thing was noted in connection with 

 the actions of crawfish before moulting. In the case of 

 adult crawfish with hard exo-skeletons, I found that for 

 two or three days before the ecdysis, they would come up 

 partly out of the water, so that the carapace was entirely 

 out of the water, and dried out thoroughly. 



Crawfish when transferred from the running water 

 tank to the still water one, would almost immediately seek 

 cover, generally burrowing into the bank, and remaining 

 during the day with their heads toward the entrance, quiet 

 unless disturbed. 



In the still water aquarium, there were at one time, six 

 crawfish hibernating in the bank, with their burrows 

 stopped up, for three weeks. The other seven in this tank 

 were in the deep water under plants during the day, but, 

 as darkness fell, they came up into the shallows and on 

 the bank. 



Kepeatedly, I have come into the building after dark- 

 ness had set in, and seldom failed to find several crawfish 

 on the bank. 



Crawfish are generally supposed to be omnivorous. 

 They are not, however, so fond of decayed matter as has 

 been supposed. Tests made in the laboratory show that, 

 when they refuse to eat stale food, they will eagerly con- 



