1915.] 



INTKODUCTION. 



7 



insects into moister regions. Essentially the same condition is pro- 

 duced during winter, when the surface soil is frozen. The common 

 mole seldom leaves its tunnels. Its nest is about 5 or 6 inches in 

 diameter and usually 12 to 18 inches beneath the surface; most fre- 

 quently it is placed under roots of shrubs or pasture grass and is 

 made of grass and rootlets, but occasionally partly of leaves. In the 

 northern half of its range the young are born during March or April; 

 in the southern part they appear earlier in spring. The number of 

 young in a litter varies from two to five, the usual number being four* 

 and there is probably only one litter produced each year. 



The habits of Scapanus are much like those of Scalopus. The 

 ridges formed by Scapanus upon the surface are usually more con- 

 spicuous than those of Scalopus, and its ^^molehiUs," thrown up at 

 frequent intervals, much larger. The hills made by Scapanus often 

 contain a half bushel or more of dirt and resemble those made by the 

 pocket gopher. The mounds made by Scapanus, however, show no 

 trace of an opening, while those of the pocket gopher do. The 

 mounds of Scapanus in most cases are more nearly circular than those 

 of the pocket gopher. So far as known, the breeding habits of sub- 

 species of Scapanus latimanus do not differ essentially from those 

 of Scalopus; the time of breeding and the number of young in a litter 

 are about the same. With Scapanus townsendii, however, the breed- 

 ing time is later, the young usually being born diu"ing May or June. 

 The number in a litter is less than with S. latimanus, there being usually 

 only two or three, seldom four, and not infrequently only one. 



The habits of Parascalops are not well known, but in general they 

 appear to be much the same as those of Scalopus. 



Star-nosed moles, genus Condylura, prefer to make their homes in 

 wet meadows or marshes, though occasionally they may choose the 

 same habitat as Scalopus, or even occupy the same tunnels with 

 them. The surface ridges made by Condylura are more irregular 

 and broken than those of Scalopus and usually smaller and more 

 crooked; the burrows seem to be deep for a short distance, then 

 appear as surface ridges, shortly to disappear again. Besides the 

 subterranean tunnels, the star-nosed mole uses surface runways 

 under and through the grass in marshes and meadows. Unhke 

 other moles, Condylura frequently leaves its tunnels in winter and 

 burrows in the snow, or even runs on top of it. Little is known con- 

 cerning the nesting and breeding habits of this genus. A family of 

 five young about one-third grown, collected May 22, 1888, by Morris 

 M. Green, and now in the Biological Survey collection, was found in 

 a nest under a log on the flats of the Potomac River a short distance 

 north of Georgetown, D. C. Two of the young from this family are 

 sUghtly more developed than the others, but it is not known whether 



