The long-eared myotis is not uncommon in and around wooded buttes. The species may be mostly limited to these areas; an individual of unknown sex found dead in a small stream southeast of Harding (several miles south of the East Short Pine Hills) is the only specimen not taken in such a situation. North of Camp Crook, on the eastern edge of the Long Pine Hills, several _M. evotis_ used an abandoned shed as a night roost in the summer of 1970; one was captured in a bat trap set at one of the entrances to the shed. Females obtained on May 29 and June 17 and 19 carried single embryos that measured 3, 14, and 15, respectively. A male young of the year taken on August 6 was nearly of adult size. Testes of two May-taken males measured 4 and 2, whereas those of one taken on July 17 and another captured on August 3 measured 6.0 and 7.5, respectively. Of seven adults collected in the period August 3 to 6, three females and two of four males were in fresh pelage; molt was nearly completed on the two remaining males. A male taken in mid-July was in an early stage of molt. New pelage is pale yellowish brown in contrast to the golden brown pelage of specimens taken in May and June. Chiggers, _Leptotrombidium myotis_ (Ewing), were found on the ears of one long-eared myotis. ~Myotis leibii ciliolabrum~ (Merriam, 1886) Small-footed Myotis Eight males of this saxicolous species were shot or netted as they foraged over a small man-made pond in wooded Deer Draw in the Slim Buttes, 10 mi. S and 5 mi. W Reva--six in late June and two in early August. Probably this bat will be found in rocky areas elsewhere in the county. One specimen taken on June 23 was molting over much of the body. ~Myotis lucifugus carissima~ Thomas, 1904 Little Brown Myotis _Specimens examined_ (27).--2 mi. N, 5 mi. W Ludlow, 1; NW 1/4 sec. 15, R. 5 E, T. 22 N, 4; NE 1/4 sec. 24, R. 8 E, T. 21 N, 20; 4 mi. S, 7 mi. W Ladner, 1; 10 mi. S, 5 mi. W Reva, 1. This bat is widely distributed in northwestern South Dakota and was the only species of _Myotis_ reported by Visher (1914:91) in his early natural history survey of Harding County. We took specimens from several of the wooded buttes and also in areas well-removed from timber; one was shot, for example, as it foraged over the Little Missouri River in the extreme western part of the county. On May 28, 1968, a barn was located in which an incipient maternal colony (several hundred adult females) roosted between double rafters supporting a metal roof. The owner of the barn, Robert Parks of Ralph, stated that bats have utilized this place as a summer roost for several years. The barn stands adjacent to the nearly treeless Big Nasty Creek, which flows through the hilly terrain of the northeastern section of the county.