. intermedius._

10'. Total length less than 119 mm.; length of upper tooth-row less
than 6.0 mm _L. ega._

Lasiurus intermedius

Northern Yellow Bat

_Diagnosis._--Upper parts yellowish-orange, or yellowish brown, or
brownish-gray faintly washed with black to pale yellowish gray;
size large (forearm, 45.2-62.8; condylocanine length, 16.9-21.5).

_Distribution and Geographic Variation_

_Lasiurus intermedius_ H. Allen, type from Matamoros, Tamaulipas, has
been reported from the Rio Grande Valley of Texas southward to Honduras
and in Cuba. _Lasiurus floridanus_ (Miller), type from Lake Kissimmee,
Florida, has been recorded from southeastern Texas, eastward along the
Gulf of Mexico to Florida, and thence northward along the Atlantic
Coast to extreme southeastern Virginia (see records of occurrence
beyond and Fig. 2). Specimens of _intermedius_ from the vicinity of the
type locality and from other localities in Mexico differ from specimens
of _floridanus_ (from Florida and southern Georgia) as follows: Larger,
both externally (especially forearm) and cranially (see measurements);
teeth larger and heavier; skull heavier and having more prominent
sagittal and lambdoidal crests; braincase less rounded, more elongate;
auditory bullae relatively smaller; upper parts averaging brighter
(yellowish to yellowish-orange in general aspect, rather than
yellowish-brown to brownish-gray).

The differences mentioned above are of the magnitude of those that
ordinarily separate subspecies of a single species rather than two
species. Miller (1902:392-393), in the original description of
_floridanus_, noted that the differences between it and _intermedius_
were slight and remarked (p. 393): "Indeed, it is probable that it
intergrades with the Texas animal." Lowery (1936:17) also has suggested
that intergradation might occur between _intermedius_ and _floridanus_
"in southwestern Louisiana or eastern Texas"; later (1943:223-224) he
pointed out that specimens from Baton Rouge, Louisiana, averaged larger
in cranial dimensions than typical _floridanus_ and again mentioned
the possibility of intergradation between the two kinds. Sanborn
(1954:25-26) touched obliquely on the problem when he wrote: "In
Florida, _Dasypterus intermedius_ is referred to as a Florida yellow
bat (_Dasypterus floridanus_)." Handley (1960:478) wrote that certain
morphological similarities suggested "gene flow" between the two kinds.

Specim