Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Order Chiroptera Blumenbach, 1779 - bats
       Family Vespertilionidae Gray, 1821 - vespertilionid bats
         Subfamily Vespertilioninae Gray, 1821
           Tribe Pipistrellini Tate, 1942
             Genus Pipistrellus Kaup, 1829 - pipistrelles
               Subgenus Pipistrellus Kaup, 1829
                 Pipistrellus hesperus Allen, 1864 - western pipistrelle
                   1 [Pipistrellus hesperus hesperus] Allen, 1864
                   2 Pipistrellus hesperus maximus Hatfield, 1936