ally grayish hue, hairiness of interfemoral membrane, and
configuration of skull described by Lukens and Davis (1957:7) for _A.
hirsutus_ are evident in all the specimens reported here. Skins of
three adults from Sonora and Chihuahua are slightly browner and
somewhat paler than skins of adults from Jalisco and Guerrero.

Reproductive data from Sonora and Chihuahua are as follows: of the five
Chihuahuan specimens, two are immature (open epiphyseal sutures); the
one adult female (79443) contained a single embryo 28 mm. in crown-rump
length. Eight of 20 Sonoran specimens taken in May are females, each of
which lacks epiphyseal sutures, and each contained one embryo. One
embryo measured 8 mm. in length of uterine enlargement; all others are
longer than 20 mm. from crown to rump, but vary in stage of
development, some having no pigmentation in the membranes and others
having pigmentation. The forearm is only 42 mm. long in one young male
from Sonora. Three of 8 Sonoran specimens taken in July had open
epiphyseal sutures but were of adult size. In summary of the
reproductive data by states, _Artibeus hirsutus_ is known to bear
embryos in the following months: May in Sonora, July in Chihuahua,
February in Jalisco, and May in Guerrero. These data, along with the
presence of embryos and young of various ages among specimens taken at
the same place and time, indicate that the species does not have a
restricted breeding season.

A geographic overlap of the ranges of _A. hirsutus_ and _A.
jamaicensis_ from Guerrero to central Sinaloa is now known. But the two
species have not been taken at the same place within this region of
overlap.

~Other species.~--At the locality on the Rio Septentrion, 1500 feet,
1-1/2 mi. SW Tocuina, Chihuahua, from which specimens of _A. hirsutus_
were obtained as mentioned previously, several other species of
tropical bats were captured, including _Desmodus rotundus murinus_
Wagner, _Glossophaga soricina leachii_ (Gray), _Chilonycteris parnellii
mexicana_ Miller, _Sturnira lilium parvidens_ Goldman, and _Chiroderma_
(specimens not yet certainly identified to species). The canyon of the
Rio Septentrion is steep and rocky, the tropical vegetation occurs only
in the bottom of the canyon, and unless construction of a railroad had
been in progress the area could have been reached only after several
days by means of a pack train. From a distributional standpoint the
occurrence of _Sturnira_ and _Chiroderma