This small Neotropical _Myotis_ has been reported from Nicaragua only from the Caribbean lowlands of Zelaya (Davis _et al._, 1964:379). Our records indicate that it is widely distributed in the republic but evidently nowhere common. Females taken on 5 March and 6 August each carried a single embryo (7 and 13 mm in crown-rump length, respectively), whereas one obtained on 21 July evidenced no reproductive activity. Richard K. LaVal currently is studying the _Myotis nigricans_ complex; pending his revision our specimens are tentatively assigned to _M. n. nigricans_. Myotis simus riparius Handley, 1960 A male (USNM 52800) from the Escondido River above Bluefields, originally reported by Miller and Allen (1928:203) as one of two _M. albescens_ from that locality, provides the first record of the species from Nicaragua and the northernmost from Middle America. The cranial dimensions of this specimen, which compare well with those listed by Handley (1960:467) for the Panamanian holotype and paratype, are: greatest length of skull, 13.8 mm; zygomatic breadth, 8.9 mm; postorbital constriction, 3.5 mm; breadth of braincase, 6.7 mm; mastoid breadth, 7.4 mm; breadth across upper molars, 5.5 mm; length of maxillary toothrow, 5.2 mm. From Nicaraguan specimens of _albescens_, the skull of the specimen of _simus_ examined (skin not seen) differs most conspicuously in having a less inflated braincase, narrower postorbital region, and a distinct sagittal crest. Eptesicus furinalis gaumeri (J. A. Allen, 1897) _Specimens._--_Carazo_: 3 km N, 4 km W Diriamba, 600 m, 7. _Chinandega_: Potosí, 5 m, 1; 6.5 km N, 1 km E Cosigüina, 10 m, 1; San Antonio, 35 m, 1. _Chontales_: 1 km N, 2.5 km W Villa Somoza, 330 m, 1; Hato Grande, 13 km S, 8 km W Juigalpa, 60 m, 3. Davis (1965:234) reported two specimens of this species from Nicaragua, one from Carazo (listed above) and the other from 1 mi SE Yalagüina, 2600 ft, Madriz. The only other specimen on record from Nicaragua is from Greytown (Miller, 1897:100). Except for two individuals that were shot as they foraged in early evening, our specimens were captured in mist nets stretched over water or as described below. Some of the bats captured northwest of Diriamba were taken in a net placed across the center of a water-filled, concrete cistern that was located in a large, open space used for drying coffee beans. Open at the top, the cistern was approximately 12 m in diameter, and the water level was approximately 3 m below the rim. Several _Artibeus jamaicensis_, _A. lituratus_, and _Molossus pretiosus_ were caught in the same net. Aside from bats removed from the net, a few _Eptesicus_ and _Molossus_ were retrieved from the water where they fell, apparently stunned, after colliding with the wall of the cistern. The fact that a number of decomposed bats of these two species were observed floating in the water indicated that such entrapment was not caused by the placement of our net.