Hatfield - 1934 Jap Ranch, Colorado R., 1¾ mi. SE 3/11 Searchlight, Clark Co. Nev. January 15, 1934. It has been supposed that these bats bring their food into such places so as not to have to eat it on the fly. However, in this case we observed no food except a few fragments of chitin of insects. When dissected, the bats' stomachs were found to be very full, so it seems strongly probable that they eat on the fly, literally gorging themselves, and then roost in some sheltered place to digest their food. These bats have relatively large eyes for Chiroptera, and seem to put them to more use than do various other bats such as Dipistrellus and Myotis. M. rufescens moves its head around in a very characteristic way, emphasizing the contraction of the back muscles, and pulling the head far back. Its ears when at rest are normally directed straight down, but when an individual is disturbed, its ears are brought into full play, being extended perpendicular to the body. These bats, in so far as known, make no noises, vocal or otherwise, even when captured. They will bite, but very seldom. Save one individual alive.