s and
probably represent _M. molossus_ as here defined.

Molossus pretiosus pretiosus Miller, 1902

_Specimens._--_Boaco_: Los Cocos, 14 km S Boaco, 220 m, 28; San
Francisco, 19 km S, 2 km E Boaco, 200 m, 3. _Carazo_: 3 km N, 4 km
W Diriamba, 600 m, 25. _Managua_: 6 mi WSW Managua, 3.

This relatively large mastiff bat has not been reported previously from
Nicaragua. Specimens from several localities in Boaco were captured in
mist nets over streams; most of those from northwest of Diriamba were
shot in the early evening as they foraged high around large trees in a
coffee finca, but several were netted over a water-filled concrete tank
or found in the water in the tank as detailed in the account of
_Eptesicus furinalis_. At Los Cocos, bats that we netted seemed to be
emerging from a hollow located high in a tree over the stream.

Selected measurements of _M. p. pretiosus_ from Nicaragua, which
compare favorably with those of topotypes from Venezuela, are listed in
Table 4 along with measurements of _M. ater_ and _M. sinaloae_. The
taxonomic relationships of _M. pretiosus_ and _M. ater_ are less than
clear, and some authors (Handley, 1966b:773, for instance) have
suggested that the two may be conspecific. Whatever their ultimate
relationships may prove to be, two distinctive taxa seem to be present
in Nicaragua; the larger is assignable to _ater_ and the smaller to
_pretiosus_, as currently understood. Furthermore, the presumed
presence of two large _Molossus_ with dark-based hairs elsewhere in
Central America (Dilford C. Carter, personal communication) and in
southeastern Mexico (Goodwin, 1956:4; Goodwin and Greenhall, 1964:20)
argues for specific recognition of _pretiosus_.

The species _ater_ and _pretiosus_ differ mainly in size (Table 4),
some measurements clearly separating the two when sexual dimorphism is
considered. Also, the average weights of 18 nonpregnant females and
four males of _pretiosus_ (all adults) collected on 20 February 1968 at
Los Cocos, were 20.9 (14.6-23.8) and 27.0 (24.6-31.7) gms, respectively,
significantly smaller than corresponding figures for 11 nonpregnant
females and nine males of _M. a. nigricans_ taken two weeks later on
the Cosigueina Peninsula--29.1 (26.1-33.0) and 32.9 (29.3-35.1) gms. It
is of note that we have not collected these two large species at the
same localities in Nicaragua, and it is possible that one competitively
excludes the other in local situations