There are multiple genera of Old World sand flies but only members of the genus Phlebotomus feed on humans and vector disease.

In the Old World, Phlebotomus and Sergentomyia, are two sand fly genera commonly found in the same survey trap. Sergentomyia spp. feed mainly on reptiles and rarely bite mammals. They sometimes transmit the protozoan parasite Sauroleishmania which does not infect mammals. Unfortunately, the inclusion of Sergentomyia spp. in molecular surveillance efforts can lead to false positives, so separating members of these genera is critical.

In some rare instances it is possible to identify specimens by using external features such as coloration, wing shape, body size, or other features, but this can be accomplished only when the local fauna is well known and only when a few species are being considered. These types of external features can be used to separate sand flies to genus when determining Old World Phlebotomus from Sergentomyia.