Within the subfamily Phlebotominae of the family Psychodidae it is estimated thatthere are approaching 1000 species and subspecies of sand flies, in five or sixgenera (depending on whether Psychodopygus is considered asubgenus or genus). Three genera – Phlebotomus,Lutzomyia and Sergentomyia – suckblood from vertebrates, the former two being the more important because theycontain disease vectors.

The genus Phlebotomus occurs only in the Old World, fromsouthern parts of northern temperate areas, mainly the Mediterranean region, tocentral Asia, and in tropical areas, but there are not many species insub-Saharan Africa or Southeast Asia and none in the Pacific area. MostPhlebotomus species inhabit semiarid and savanna areas inpreference to forests. Lutzomyia species are found only in theNew World, and, by contrast, occur mainly in forested areas of Central and SouthAmerica.

Sergentomyia species are also confined to the Old World, beingfound mainly in the Indian subregion, sub-Saharan Africa and Asia. Although afew species bite people they are not vectors.

The medically most important species include Phlebotomus papatasi, P.sergenti, P. argentipes, P. ariasi, P. perniciosus and species inthe Lutzomyia longipalpis and L.flaviscutellata species complexes. In both the Old and New Worldssand flies are vectors of leishmaniasis and viruses responsible for sand flyfever, and in theAndes the bacterium Bartonella bacilliformis,causing bartonellosis (Carrión’s disease).