Walter Woelber Dalquest

“ Our examination of American specimens reveals only one differential character: In Myotis the outer upper incisor is distinctly larger than the inner, whereas the two incisors are of approximately equal size in Pipistrellus. It may be noted that the outer upper incisor of several, but not all, species of Myotis has a well-developed concave surface directed toward the canine whereas this surface is flat or convex in Pipistrellus. In both features, the type of Pipistrellus cinnamomeus Miller agrees with Myotis and differs from Pipistrellus. ”

“ In preparing this taxonomic account of bats of the genus Myotis, the specimens (type and two from Papayo) of Pipistrellus cinnamomeus seem not to have been examined. Indeed, it is almost certain that they were not examined for the species was renamed; the new [Pg 585] name, Myotis lucifugus fortidens Miller and Allen (Bull. U. S. Nat. Mus., 144:54, May 25, 1928) , was based on a skull with the corresponding body in alcohol. The characters of this specimen are almost exactly those of Pipistrellus cinnamomeus, named and described by Miller 26 years earlier. The type locality (Teapa) of M. l. ”

“ It may reasonably be asked if Myotis and Pipistrellus should be retained as separate genera if the only constant difference between the two is subequal versus unequal upper incisors. In our opinion it would be worth-while for someone who had access to adequate material from both the Old World and the New World to investigate this question. We lack adequate material from the Old World.
When Miller and Allen named M. l. ”