ORTMANN : THE CKAWFJSHES OF THE STATE OF PENNSYLVANIA 479 



Andrews (1904, p. 166) places the normal mating season in the months of February, 

 March, and the beginning of April, and says that there seems to be an autumnal 

 pairing (October, November) "in place of or in addition to " the spring pairing. I 

 believe, however, that the autumnal pairing is the normal one, which may be 

 extended through the winter. Indeed I have observed it in January, but only in 

 specimens kept in ca])tivity. Since Andrews' observations were made in the labora- 

 tory, it appears probable that the mating may be continued or repeated under exce])- 

 tional conditions such as are offered in captivity, but that this is not normal, in 

 C. obscurus I am positive that under natural conditions copulation does not take 

 place in March and April. 



The time of spawning, as observed by Andrews (1904, p. 176) agrees well with 

 our records (end of March and April), also the time of hatching (/. c, p. 187), late 

 in ]\Iay. 



As to sexual maturity, Andrews did not gather facts to show that females are 

 mature and oviposit at the end of the first year (1904, p. 206), although he observed 

 copulation at the end of the first summer. I observed, on November 4, 1905, copu- 

 lation taking place in specimens less tban 45 mm. long, and found females "in 

 berry " of the size of 50 and 45 mm. (Cumberland, May 9, 1905). Since the same 

 fact has been observed in the case of C. obscurus it is certain that males as well as 

 females are sexually mature at the end of the first summer, and that the sexual 

 union is effective, the females spawning the following spring. However, in such 

 small females the number of eggs is generally very small (fifty or less). 



Thus it seems that C. Ilmosus agrees perfectly with ('. obscuru.'< in its life-history, 

 and that the only marked ditt'erence from Andrews' account concerns the mating 

 season. Tliis is however apparently due to the fact that Andrews' observations were 

 made in the laboratory. The explanation for this is very likely U) be sought in the 

 temperature conditions. The water used in tanks in laboratories has generally a 

 rather uniform temperature throughout the year, while umler natural conditions the 

 temperature of ponds, rivers, and streams varies considerably in summer and winter. 

 I made a few observations with reference to C. obscnriis. In .January, under the ice, 

 the water is near the freezing point, say about 35° F. ; on April 6, when females 

 were found spawning, the temperature of Thorn Creek, Butler County, was 45° F. 

 On May 1 the temperature of Grave Creek, Mai-shall County, West N'irginia, was 

 66° F. and spring moulttiig was going on. In midsummer I observed a temperature 

 of 82° F. in Bates Fork, Greene County, on July 21, and a temperature of 78° F. in 

 the Ohio, at Ambridge in Beaver County on August 24. 



This gives a range of from about 35 to 80 during the vear, and 1 have no doubt 



