Specific Characters in Tarsal Claws of Some Species of Aedes ’

Certain species of Aedes occurring in North America have been considered difficult if not impossible to identify from adult females alone. Five band-legged species, Aedes excrucians (Walker), A. stimulans (Walker), A. fitchii (F. & Y.), A. riparius D. & K., and A. increpitus Dyar, are in this class. They form a compact group, and female specimens have been very difficult to identify with assurance. Matheson (1944) used mesonotal colour and mesepimeral bristling for separating most specimens of these species. To these characters Gjullin (1946) added the colour of the torus and of the palp, but he also was unable to definitely identify some specimens of excrucians and fitchii. Ross (1947) used the characters employed by Matheson to separate stimulans, fitchii, and excrucians, but admitted that the characters are often unsatisfactory. While comparing female specimens of excrucians and fitchii, the writer was surprised to note a very distinct difference in the shape of the tarsal claws of the two species. A review of the literature on the five species of this band-legged group showed that the value of specific characters in the tarsal claws had bee