| _M. p. uligocola_, Colorado | Park Co. (Denv) | 7 | 12.20 | 9.40 | 7.07 | 3.60 | 7.91 | Boulder Co. (Chi) | 30 | 12.14 | 9.24 | 7.07 | 3.36 | 7.85 | Denver | 8 | 12.23 | 9.35 | 7.27 | 3.55 | 7.99 | Colorado Springs | 16 | 12.18 | 9.22 | 7.20 | 3.43 | 7.89 | Loveland, mean | 16 | 12.31 | 9.46 | 7.14 | 3.59 | 8.14 | " , stand. dev. | ... | .65 | .41 | .32 | .16 | .42 | " , minimum | ... | 11.4 | 9.0 | 6.8 | 3.3 | 7.5 | " , maximum | ... | 13.8 | 10.6 | 7.6 | 3.8 | 9.4 | ------------------------+------+--------+-------+-------+---------+------- | | _M. p. finitus_ | Wray, Colorado | 3 | 12.30 | 9.43 | 7.40 | 3.53 | 8.23 | Dundy Co., Nebr., mean | 12 | 12.64 | 9.39 | 7.52 | 3.66 | 8.22 | " " , stand. dev. | ... | .61 | .40 | .31 | .26 | .43 | " " , minimum | ... | 11.6 | 8.5 | 7.0 | 3.2 | 7.6 | " " , maximum | ... | 13.5 | 9.8 | 7.9 | 3.9 | 8.7 | ------------------------+------+--------+-------+-------+---------+------- | | _M. p. modestus_, Colorado | Alamosa, Colorado | 3 | 11.97 | 9.27 | 6.83 | 3.60 | 8.01 | Cochetopa Pass, Colo. | 25[1]| 12.16 | 9.04 | 6.81 | 3.54 | 8.18 | " , stand. dev. | ... | .37 | .31 | .21 | .14 | .23 | " , minimum | ... | 11.4 | 8.6 | 6.5 | 3.3 | 7.7 | " , maximum | ... | 13.1 | 10.0 | 7.5 | 3.9 | 8.8 | ------------------------+------+--------+-------+-------+---------+------- [1] 29 specimens were used in taking measurements of the skull. _Remarks._--Bailey (1900:20) had only 7 specimens from northeastern Wyoming and western South Dakota, of _M. pennsylvanicus_ and thought that _Arvicola insperatus_ Allen (1894:347) was not subspecifically distinct from _modestus_. Subsequently Bailey (1920:72) had adequate numbers of specimens and described _Microtus pennsylvanicus wahema_ from eastern Montana and western North Dakota. Anderson (1943:92) concluded that _wahema_ was not distinct from _insperatus_ and therefore the name _M. p. insperatus_ (Allen) is applicable to this subspecies. On the basis of specimens that I have examined from Montana, South Dakota, and Wyoming I concur with Anderson. Bailey's characterization of _wahema_ is applicable to _insperatus_ as I interpret it. In the Black Hills, _Microtus longicaudus longicaudus_ (Merriam) occurs together with _insperatus_.