Six species of bats were recorded from Barro Colorado Island by Professor Robert K. Enders in his "Mammalian Life Histories from Barro Colorado Island, Panama" (Bull. Mus. Comp. Zool., at Harvard College, 78: 383-502, 5 pls., October, 1935). With his list as a starting place we can offer a revised list as follows: Saccopteryx bilineata (Temminck).--Nos. 45061, 45062, 45097, and 402 and 404 of Jackson. Nonpregnant female No. 45061 captured on April 3 weighed 7.0 grams; No. 45062 captured on April 4 contained one embryo 22 mm. long. It was common to see several bats of this species, not in a cluster but with a few inches of space between any one bat and its neighbors, on the vertical screens that covered the airways beneath the eaves of the buildings. A colony was established in Zetek House (a trail-end house on the western side of the Island), and several individuals often were seen in the Tower House. As many as 50 individuals could be found at the Van Tyne Big Tree (_Bombacopsis Fendleri_) where they hung singly in the shaded inter-buttress spaces and on the exposed trunk sometimes up to a height of 100 feet. Occasionally several individuals would be seen in inter-buttress spaces of large trees on other parts of the Island. These bats were more alert during the daylight hours than were most other kinds of bats and could be approached and captured only with considerable difficulty. From the various colonies 13 females and 3 males were banded. Noctilio leporinus mexicanus Goldman.--Seen in Wheeler Estuary by Enders (_op. cit._:416) who uses the subspecific name _N. l. leporinus_. Goodwin (Bull. Amer. Mus. Nat. Hist., 79:121, May 29, 1942) later used the subspecific name _N. l. mexicanus_ for this species in Panama. Micronycteris megalotis microtis Miller.--Enders (_op. cit._:417) obtained specimens of this species from the underside of a fallen log and in a hollow tree at marker No. 23 on the Pearson Trail. Phyllostomus discolor discolor Wagner.--Taken from a hollow tree by Enders (_op. cit._:417). Glossophaga soricina leachii (Gray).--No. 45073, April 5. Carollia perspicillata azteca Saussure.--No. 400 of Jackson taken at Allee Creek and Barbara Lathrop Trail and No. 52456 (410 of Jackson) at Termite Cemetery. These two nonpregnant females weighed 14.7 and 17.7 grams, respectively. Two ([Male] and [Female]), caught at Termite Cemetery were banded and released. Carollia castanea H. Allen.--Males, 45080 and 45081, weighed 11.8 and 11.5 grams; at 9:30 P.M., on April 6, on Barbara Lathrop Trail. Vampyrops helleri Peters.--Male, No. 45095, in net on April 4; weighed 15 grams.