ures, restricted geographic distribution, and the
lack of evidence of intergradation between it and _crawfordi_.

_=Balantiopteryx plicata pallida=_ Burt.--Thirty-five specimens from two
adjacent localities along the R['i]o del Fuerte in northern Sinaloa, 3 mi.
NE San Miguel, 300 ft. (84944-48) and 10 mi. NNE Los Mochis (60572-75,
60667-78, 60681-94), provide the first records of the subspecies from
the state. Individuals from both localities were shot at dusk as they
foraged among trees in the valley of the river. Fifteen of 18 females
from 10 mi. NNE Los Mochis, collected on June 5, 6 and 7, 1955, were
pregnant; each contained a single embryo, the embryos ranging from 7 to
15 mm. in crown-rump length. _B. p. pallida_ previously has been
reported from the southern parts of Baja California and Sonora.

_=Balantiopteryx plicata plicata=_ Peters.--Specimens in the Museum of
Natural History from the following localities, several of which are
marginal, document better than previously has been done the distribution
of this subspecies in Sinaloa: 32 mi. SSE Culiac['a]n (60699); 10 mi. SE
Escuinapa (68629); 17 mi. SSE Guamuchil (60576); 5 mi. NW Mazatl['a]n
(85537-61, 85901-04); 1 mi. SE Mazatl['a]n, 10 ft. (39461-76); 1 mi. S
Pericos (60697-98, 60700); 1/2 mi. E Piaxtla (60701); 1/2 mi. W Rosario,
100 ft. (39477-79); 5 mi. SSE Rosario (60702-03); 4 mi. N Terrero
(60695-96).

Pregnant females, each with a single embryo, were recorded in 1954 from
4 mi. N Terrero, 2 (June 9), 1 mi. S Pericos, 2 (June 13), and 5 mi. SSE
Rosario, 2 (June 20). None of 16 December-taken females from 5 mi. NW
Mazatl['a]n was pregnant.

The specimen from 17 mi. SSE Guamuchil, preserved in alcohol, is
provisionally referred to _B. p. plicata_ on geographic grounds inasmuch
as specimens from the nearby localities of 1 mi. S Pericos and 4 mi. N
Terrero, although more grayish on the average than specimens from
southern Sinaloa, are somewhat darker and distinctly larger than
specimens of _B. p. pallida_ from along the R['i]o del Fuerte in northern
Sinaloa. Specimens from southern Sinaloa average only slightly paler
than typical _plicata_ examined from southern M['e]xico and Nicaragua.

_=Pteronotus psilotis=_ (Dobson).--A total of six specimens from two
localities in southern Sinaloa provide the first records from the state
and are the northernmost records in western M['e]xico. The two localities
are: 1/2 mi. S Concepci['o]n, 250 ft. (84987-90); 1 mi.