Six species of mites (Ixodoidea excepted) were found on the prairie vole. Four of these were collected also from other small mammals living in the same habitat as this vole. Two species of mites were found to occur on voles in New York, Kansas, and California. TICKS (IXODOIDEA) Two kinds of ticks were found. One adult specimen of _Ixodes sculptus_ Neumann was clinging to the head of a vole, just in front of its eye. This species of tick was taken also from the thirteen-lined ground squirrel (_Citellus tridecimlineatus_) at Lawrence. One nymph of _Dermacentor variabilis_ (Say) was found attached to the scapular region of a prairie vole. Both of these specimens were taken in June. TABLE 7. _Host Distribution of Mites on Seven Small Mammals_[F] Column headings: A: _Scalopus aquaticus_ B: _Cryptotis parva_ C: _Blarina brevicauda_ D: _Peromyscus maniculatus_ E: _Peromyscus leucopus_ F: _Sigmodon hispidus_ G: _Microtus ochrogaster_ A B C D E F G ------------------------------------------------------------------------- _Ascoschöngastia brevipes_ (Ewing) .. .. .. .. X X X _Liponyssus occidentalis_ Ewing .. X .. .. .. .. .. _Eulaelaps stabularis_ (Koch) X X X .. X .. X _Atricholaelaps glasgowi_ (Ewing) .. .. .. X .. .. X _Atricholaelaps sigmodoni_ Strandtmann .. .. .. .. .. X .. _Laelaps kochi_ Oudemans .. .. .. .. .. X X _Myocoptes_ sp. .. .. .. .. .. .. X _Listrophorus_ sp. .. .. .. .. .. .. X ------------------------------------------------------------------------- [Footnote F: These data are from material collected at Lawrence, Douglas County, Kansas.] REPRODUCTION AGE CLASSES Each prairie vole was assigned to one of three age classes (juvenile, subadult, or adult) principally on the basis of weight, but partly on the quality and color of the pelage. The three age classes are characterized in table 8. TABLE 8. _Characters of Juvenile, Subadult, and Adult Prairie Voles_ Juvenile Subadult Adult Less than 21 grams 21-38 grams 38 grams or more Weight usually less Average weight Average weight than 20 grams 30-32 grams 40-45 grams Entire pelage dull Pelage of rump Pelage usually dull; rest of entirely glossy pelage glossy (rump sometimes dull) Dorsal color black Dorsal color Entire dorsal color grizzled except grizzled except on rump sometimes on rump FECUNDITY