Four nominal species of the genus Pipistrellus are currently recognized in North America. They are Pipistrellus subflavus (F. Cuvier) of eastern North America, Pipistrellus hesperus (H. Allen) of western North America, Pipistrellus veracrucis (Ward) from Veracruz, Mexico, and Pipistrellus cinnamomeus Miller from Tabasco, Mexico.

In the past three years, specimens have been obtained in Veracruz (by Dalquest) of each of the southern species. One of these, P. cinnamomeus, previously was known from a single specimen; the other, P. veracrucis, was known only from six specimens which now are lost or misplaced. The results of our study of these recently acquired Mexican specimens constitute our principal contribution in this paper; we have done little more with the material from the United States and Canada than to codify the findings of other mammalogists with respect to the systematic status and geographic distribution.