Microtus (Pitymys) pinetorum (LeConte)
Figs. 27 and 28
Baculum: Stalk broad, greatest length (2.5 to 2.7 mm.) 12/3 times greatest breadth, 4 times greatest depth; median process ossified, size small, 1/5 length of stalk, higher than wide, having small anterodorsal prominence in both specimens examined; lateral processes cartilaginous, relatively small, displaced posteriorly, attenuate; posterior margin in dorsal view broadly rounded, or having blunt median apex, convex throughout; basal tuberosities moderately well developed, medially confluent, barely visible in dorsal view when mature; in end-view median constriction 4/5 greatest depth, ventral concavity deeper than dorsal concavity, both comparatively shallow; stalk at mid-point 1½ times as wide as deep; shaft relatively slender, bowed dorsally at tip, relatively straight otherwise; lateral profile in dorsal view a gradual concave slope from point of greatest width anteriorly to distal part of shaft.
Specimens examined: Two, from Douglas Co., Kansas, 76834 (2 mi. N Baldwin), 68545 (1 mi. NE Pleasant Grove).
Microtus (Pitymys) parvulus (Howell)
Fig. 40
Baculum: Stalk broad, greatest length (2.4 mm. in specimen examined) 1¾ times greatest breadth, 4 times greatest depth; median process ossified, size small, less than ¼ length of stalk, wider than high, terminally flattened; lateral processes cartilaginous, relatively small, attenuate; posterior margin in dorsal view flattened, irregularly curved with concavities medially and laterally; basal tuberosities well developed, medially confluent; visible in dorsal view; in end-view median constriction 2/3 greatest depth, ventral concavity well-formed, no dorsal concavity; stalk at mid-point twice as wide as deep; shaft relatively slender, bowed dorsally toward tip; in dorsal view lateral profile a gradual concave slope from point of greatest width anteriorly to distal part of shaft; tip of shaft enlarged.
The baculum of M. parvulus resembles that of M. pinetorum more than it resembles the baculum of any other microtine studied, differing primarily in smaller size.
Specimen examined: One, from 1 mi. W Micanopy, Alachua Co., Florida, Univ. Florida No. 1508.