472 MEMOIRS OF THE CARNEGIE MUSEUM 



form, 81 mm. long, which was lying concealed under a rock in the usual position. 

 It was absolutely perfect, without Ijlemish, and with an old, very dirty shell, thus 

 clearly showing that it had gone through the previous winter. This specimen was 

 barely alive and to all appearances in a dying condition. A similar instance was 

 noticed on April 24, 1905, in Wheeling Creek, Elm Grove, West Virginia. Here a 

 large male of the first form (81 mm. long) was found showing no signs of injury, in 

 fact in very beautiful condition, but barely able to move. It was kept in water, 

 but was dead the next day, wliile other specimens collected together with it were 

 none the worse for their journey to Pittsburgh. Thus it seems that the conclusion 

 is justified that the largest males of the first form, after having in the autumn at- 

 tained a certain maximum size, which may be different according to conditions, Init 

 may be said in general to be about 80 mm. in length, go through the winter, but do 

 not moult again, and die a natural death in spring.'" 



The latest dates at which I found males of the first form in spring are as fol- 

 lows : June G, 1904, Linesville (the case just mentioned), May 30, 1901, at Waynes- 

 burg, Greene County ; May 25, 1905, Alleghany River, Mosgrove, Armstrong 

 County. After the beginning of June, all through the month, and through a large 

 part of July, no males of the first form have been found, and through the remainder 

 of July they are scarce. (See below.) 



The eges carried by the females hatch at the end of May and the beginning of 

 June. I found young under the abdomen of the mother on May 30, 1904, on June 

 5, 1906, and on June 6, 1904. The period daring which the young stay with the 

 mother seems to be sliort. On May 25, 1905, I found eggs, not yet hatched. From 

 June 15, 1905, onward all through the remainder of the year I never observed a 

 female with eggs or young. Between these two dates I have only four records, May 

 30, 1904, June 2, 1905, June 5, 1906 and June 6, 1904, in three of which the pres- 

 ence of young ones with the mother was shown. Thus the period when j^oung are 

 found under the abdomen of the mother is very likely the end of May and first half 

 of June (about three weeks), and the young crawfishes probably do not remain with 

 the mother much longer than a week. 



Throughout June and part of July no niales of the first form are present ; all 

 males are of the second form, but they are not very large, reaching a maximum size 

 of only between 60 and TO mm. The females have got rid of their progeny, and 

 begin to pioult. The old females may die like the old males, but I have no evi- 

 dence on this point, except as drawn from analogy to the males, and the fact that 



'° A great mortality of males in spring (after copulation in captivity) has been observed by Andrews ( 1904, p. 

 175) in C. limoaus. 



