1. M. (Pitymys) fatioi, 67103, Zermatt, Switzerland, immature.
  2. M. (Pitymys) pinetorum, 76834, 2 mi. N Baldwin, Douglas Co., Kansas.
  3. M. (Pitymys) pinetorum, 68545, 1 mi. NE Pleasant Grove, Kansas.
  4. M. (Pitymys) quasiator, 30709, Teocelo, Veracruz, (d) ventral view.
  5. M. (Pitymys) quasiator, 19878, 5 km. N Jalapa, Veracruz.
  6. M. (Pedomys) ochrogaster, 75036, 1 mi. N, 2 mi. E Oberlin, Kansas.
  7. M. (Stenocranius) miurus, 51152, Lake Schrader, Brooks Range, Alaska.
  8. M. (Stenocranius) miurus, 51169, Lake Schrader, Brooks Range, Alaska.
  9. M. (Stenocranius) gregalis, 8059, "Eastern Europe."
  10. M. mexicanus mexicanus, 63094, Valle de Bravo, Estado de México, México.
  11. M. mexicanus mogollonensis, 63298, Mt. Taylor, Valencia Co., New Mexico.
  12. M. californicus, 76828, 1 mi. NE Berkeley, California; (d) ventral view.
  13. M. (Arvicola) richardsoni, 42454, 31 mi. N Pinedale, Sublette Co., Wyoming.
  14. M. richardsoni, 37903, 23-1/2 mi. S, 5 mi. W Lander, Wyoming; distal end.

Figures 40-49. Bacula of microtines. Unless indicated otherwise views are (a) of the dorsum, (b) the right side, and (c) the proximal end with the dorsal surface upward.

  1. Microtus (Pitymys) parvulus, UF 1508, 1 mi. W Micanopy, Florida.
  2. Microtus townsendii, 79186, Sec. 33, T. 11S, R. 5W, Benton Co., Oregon.
  3. Microtus (Herpetomys) guatemalensis, 65895, 2 mi. S San Juan Ixcoy, Guatemala.
  4. M. guatemalensis, 65921, 10 mi. E, 4 mi. S Totonicapan, Guatemala, dorsal view of tip.
  5. Microtus oeconomus, 43048, Kelsall Lake, British Columbia.
  6. Microtus (Chilotus) oregoni, WBQ 3-C-248, 5 mi. N Orick, California.
  7. Lagurus (Lemmiscus) curtatus, 26053, 9 mi. S Robertson, Uinta Co., Wyoming.
  8. Microtus (Chionomys) nivalis, 65127, Wetterstein, Germany, orientation uncertain.
  9. Microtus (Chionomys) longicaudus, 50253, Crane Flat, Mariposa Co., California.
  10. Neofiber alleni, 27268, 2 mi. S Gainesville, Florida, orientation uncertain.

(Microtus) provectus (the last three are probably insular derivatives of M. pennsylvanicus), M. (Microtus) fulviventer (perhaps derived from the same stock as Microtus mexicanus), M. (Microtus) xanthognathus (perhaps related to Microtus chrotorrhinus), M. (Microtus) coronarius, and M. (Pedomys) ludovicianus.

Species of Which Bacula Were Examined
Subfamily: MicrotinaeNumber of Specimens
Tribe: Lemmi
Dicrostonyx groenlandicus (Traill)4
Lemmus trimucronatus (Richardson)6
Synaptomys cooperi Baird5
Tribe: Microti
Genus: Clethrionomys Tilesius, 1850
Clethrionomys rutilus Pallas4
Clethrionomys gapperi (Vigors)9
Clethrionomys occidentalis (Merriam)1
Clethrionomys glareolus Schreber1
Clethrionomys rufocanus Sundevall1
Genus: Phenacomys Merriam, 1897
Phenacomys intermedius Merriam5
Genus: Ondatra Link, 1795
Ondatra zibethicus (Linnaeus)1
Genus: Microtus Schrank, 1798
(Herpetomys) guatemalensis Merriam3
(Arvicola) richardsoni (DeKay)2
(Chilotus) oregoni (Bachman)3
(Stenocranius) gregalis (Pallas)1
(Stenocranius) miurus Osgood9
(Chionomys) longicaudus (Merriam)6
(Chionomys) nivalis Martins2
(Microtus) arvalis (Pallas)1
(Microtus) orcadensis Millais1
(Microtus) guentheri Danford and Alston1
(Microtus) fortis Büchner2
(Microtus) montanus (Peale)15
(Microtus) townsendii (Bachman)3
(Microtus) oeconomus (Pallas)10
(Microtus) mexicanus (Saussure)13
(Microtus) californicus (Peale)2
(Microtus) pennsylvanicus (Ord)13
(Microtus) agrestis (Linnaeus)1
(Pedomys) ochrogaster (Wagner)41
(Pitymys) pinetorum (LeConte)2
(Pitymys) parvulus (Howell)1
(Pitymys) quasiater (Coues)5
(Pitymys) fatioi Mottaz1
Genus: Neofiber True, 1884
Neofiber alleni True2
Genus: Lagurus Gloger, 1841
Lagurus curtatus (Cope)7
Total number examined184

ACCOUNTS OF SPECIES