14 



ISrOKTH AMEEICAN- FAUNA. 



[No. 88. 



during October, thougli occasionally it begins the last of September; 

 the full winter pelage is usually obtained before the last of October. 



In a large series of Neilrotrichus from Sumas, British Columbia, 

 the spring molt appears to be at its height during the latter haK of 

 May and the first week of June, though one or two specimens indicate ' 

 a beginning of the molt as early as the latter part of April; most 

 individuals are in full summer pelage by the first of July; none of 

 these specimens show autumnal molt. Farther south, in Washington, 

 Oregon, and northern California, spring molt is earlier, and specimens 

 taken there during the first part and middle of June are in summer 

 pelage. The available material has been insufficient to determine 

 the time of the fall molt, though apparently it occurs during October. 

 A specimen from Goldbeach, Oreg., collected September 21, 1901, 

 has a trace of new pelage under the old on the breast; two from 

 Steilacoom, Wash., October 9 and 12, 1891, and one from Palo 

 Alto, Cal., October 17, 1897, have the molt well advanced; a male 

 taken October 18, 1891, at Tenino, Wash., is in nearly complete 

 winter pelage. 



MANNER OF MOLTING. 



Molting in Scalopus occurs more or less regularly in definite 

 sequence on the different parts of the body, and the same order is 

 followed in both the vernal and autumnal molts. The fresh pelage 

 first appears on the breast and abdomen (PI. I, fig. 1) and gradually 

 replaces the old until the entire underparts, except the chin and 

 throat, have molted; at this stage there is a sharp lateral line of 

 demarcation between the new and the old fiu* (PL I, fig. 2) ; the fresh 

 * pelage gradually extends up over the back, generally encroaching 

 upon the posterior part first and working forward toward the nose. 

 The chin and throat in most individuals retain the old pelage for 

 several days after all the rest of the molt is complete. There are, 

 of course, exceptions to this general order of molting but most of 

 these occur in animals which are molting either earlier or later 

 than normally, and the writer is inclined to believe that these varia- 

 tions are either due to retarded or stimulated physiological processes, 

 or else result from injuries to the animal. Two specimens show 

 distinctly that the molting process has been retarded on account 

 of injuries; one ^ is in full winter pelage except a very small place 

 on the throat and a small patch directly posterior to a flesh wound 

 on the left side of the posterior part of the back; the other ^ is in 

 complete winter pelage except a circular patch, about 20 mm. in 

 diameter on the occiput, which is also mostly posterior to a flesh 



1 No. 180769, U. S. Nat. Mus., Biological Survey collection; cf adult, collected at Washington, D. C, 

 October 11, 1912. 



a No. 6190. Acad. Nat. Sci. Philadelphia; ? adult, collected at Audubon, N. J., October 28, 1908. 



