12 



NOETH AMERICAN" FAUNA. 



[No, 38. 



the spring molt in that region occurs usually during the months of 

 April and May, though most of the animals are probably in full sum- 

 mer pelage by the middle of May. A large series of specimens from 

 the same locahty, taken during October and the first part of Novem- 

 ber, are all in full winter pelage; the fall molt seems to take place 

 there during the latter part of August and the first half of September. 

 Specimens of Scalopus aquaticus machrinus from northern Illinois 

 show molting during the first half of May; one taken June 15, 1907, 

 at Johet, 111., is in fresh summer pelage, except for a smaU place on 

 the face; in a topotype of S. a. machrinus collected September 5, 1898, 

 the ventral parts are in short, fresh, winter pelage, the dorsal parts 

 in old, summer pelage. Specimens of S. a. pulclier, taken at Dehght, 

 Ark., the middle of September, are in nearly complete winter fur; an 

 adult male taken April 30, 1910, at Lake City, Ark., is in fresh sum- 

 mer pelage except on the nose; specimens taken at Sour Lake, Tex., 

 the latter part of March and first of April, 1905, show the beginning 

 of molt on the underparts. The spring molt of S. a. australis seems 

 to occur from about the middle of March to the middle of April. A 

 topotype of S. a. texanus, collected February 9, 1893, has fresh 

 summer pelage on the abdomen. 



The time of molting seems to be more irregular in Scapanus than 

 in Scalopus, and the period of seasonal molt during which numbers 

 of individuals may be found molting is more prolonged than with 

 Scalopus; it is possible that this difference may be correlated with 

 climatic differences. The spring molt in Scapanus latimanus lati- 

 manus may commence any time from the middle of January to the 

 last of April; specimens ia which the spring molt has just begun were 

 collected at Santa Cruz, Cal., January 14 and February 28, and at 

 Red Bluff, Cal., April 24; one collected at Lower Lake, Cal., April 12, 

 still retains the wOrn and faded winter pelage; a specimen collected 

 March 13, at Santa Cruz, is in fresh summer pelage, and the majority 

 of specimens show this condition by the middle of April. The 

 autumnal molt of S. I. latimanus may begin from the middle of August 

 to the last of November; in a male collected August 14, at Santa 

 Cruz, the molt is well begun; a specimen taken November 30 at 

 Fort Bragg, Cal., has fresh pelage on the head only, and another 

 taken the same day at King City, Cal., has obtained about one-third 

 of its new pelage; in most cases, however, the winter pelage is com- 

 plete by the last of November. The autumnal molt in ^S'. I, dilatus is 

 usually completed a month earher than in S. I. latimanus, though one 

 specimen collected at Chico, Cal., December 20, has just started to 

 molt. A female collected August 4, at Round Mountain, Cal., is 

 about two-thirds covered with fresh pelage, and is probably in a 

 delayed spring molt. The specimens of S. I. occultus examined indi- 

 cate that the spring molt in that form may begin as early as the first 



