of Arteaga; they were obtained during
the day, at which time they were actively moving about in the leaf
litter along a small stream.

These frogs are all referred to _M. pygmaeus_, because this is the
earliest name available for frogs showing the variation in
characteristics displayed by this large series. The characters used by
Taylor (1936a, 1940d, 1941a, and 1942b) and Smith and Taylor (1948) to
distinguish the various species of _Microbatrachylus_ include color
pattern, relative length of the hind limb, presence and position of
dorsal dermal folds or pustules, relative size of inner and outer
metatarsal tubercles, and the number of palmar tubercles. All specimens
from Arteaga have two palmar tubercles; the inner and outer metatarsal
tubercles are subequal in size. Furthermore, aside from sexual
difference, there is little variation in the relative length of the hind
limbs (Table 3). However, many color patterns do exist in the series;
each of these color patterns is described below.

TABLE 3.--SNOUT-VENT LENGTH EXPRESSED AS A PERCENTAGE OF TIBIA LENGTH IN
ANIMALS OF SIX COLOR PATTERNS OF MICROBATRACHYLUS PYGMAEUS. (LETTERS
REFER TO THE VARIANTS HAVING THE COLOR PATTERN DISCUSSED IMMEDIATELY
BELOW)

+------------+-----------+---------+---------+----+--------+
| | | Number | Range | | Twice |
| Color | Sex | of | of |Mean|standard|
|Pattern | |specimens|variation| | error |
| | | | | |of mean |
+------------+-----------+---------+---------+----+--------+
| A | Male | 25 |51.4-57.5|55.2| 3.34 |
| | Female | 25 |49.3-54.9|51.6| 3.12 |
| B | Male | 20 |51.0-57.1|55.4| 2.44 |
| | Female | 21 |47.3-54.9|51.2| 3.52 |
| C | Male | 6 |54.5-56.2|55.2| .... |
| | Female | 6 |50.0-52.9|51.6| .... |
| D | Male | 17 |52.9-58.2|55.4| 2.64 |
| | Female | 14 |48.5-56.6|52.1| 4.16 |
| E | Male | 10 |50.9-56.9|55.1| 3.40 |
| | Female | 7 |49.6-54.5|51.6| .... |
| F | Female | 2 |51.9-52.6|52.3| .... |
+------------+-----------+---------+---------+----+--------+

A.--225 specimens: Dorsum mottled brown and cream, usually with a dark
spot between the eyes and one or two dark V-shaped marks with