32 Field Museum of Natural History — Zoology, Vol. XL 



Subgenus OCHROTOMYS. 

 Peromyscus nuUalli aureolus (Aud. and Bach.)- Southern Golden Mouse. 

 Genus REITHRODONTOMYS. 



[Reithrodontomys dychei Allen, Dyche's Harvest Mouse.] 



Genus ORYZOMYS. 

 Oryzomys palustris (Harlan). Rice Field Mouse. 



Subfamily NEOTOMIN/E. 



Genus NEOTOMA. 

 Subgenus NEOTOMA. 

 Neotoma floridana illinoensis Howell. Illinois Wood Rat. 



Subfamily MICROTIN^. 

 Genus EVOTOMYS. 

 Evotomys gapperi (Vigors). Red-backed Mouse or Vole. 



Genus MICROTUS. 

 Subgenus MICROTUS. 

 Microtus pennsylvanicus (Ord). Meadow Mouse or Vole. 



Subgenus PEDOMYS. 

 Microtus ochrogaster (Wagner). Prairie Meadow Mouse or Vole. 

 [Microtus minor Merriam. Little Meadow Mouse or Vole.] 



Subgenus PITYMYS. 

 Microtus pinetorum scalopsoides (Aud. and Bach.). Mole Mouse or Mole-like Vole. 



Genus FIBER. 

 Fiber zihethicus (Linn.). Muskrat. 



Genus SYNAPTOMYS. 

 Subgenus SYNAPTOMYS. 

 S ynaptomys cooperi Baird. Cooper's Lemming Mouse.]* 

 Synaptomys cooperi gossii (Merriam). Goss's Lemming Mouse. 

 S ynaptomys cooperi fatuus (Bangs). Bangs's Lemming Mouse. 



Family GEOMYIDiE. Pocket Gophers. 

 Genus GEOMYS. 



Geomys hursarius (Shaw). Pocket Gopher. 



Family ZAPODIDiE. Jumping Mice. 

 Subfamily ZAPODIN^. 

 Genus ZAPUS. 

 Zapus hudsonius (Zimm.). Hudson Bay Jumping Mouse. 



Genus NAP^OZAPUS. 

 [Napoeozapus insignis (Miller). Woodland Jumping Mouse.] 



*I have seen no typical specimens of 5. cooperi from Illinois, but specimens from the east 

 central part of the state are intermediate between cooperi and gossii. 



