The spiracle indices were determined in 1153 specimens from 5 species of the subgenus Larroussius (Diptera, Phlebotominae): Phlebotomus neglectus, P. perfiliewi, P. tobbi, P. kandelakii, and P. smirnovi) and 2 species of the subgenus Adlerius: P. brevis and P. longiductus. These species are all documented or potential vectors of Leishmania infantum, the causative agent of visceral leishmaniasis. The spiracle index is related to the rate of its evaporization and it is an important ecological index that assesses its behaviour, the time and conditions of its activity, its shelter, which in turn makes it possible to differentiate methods for controlling and preventing visceral leishmaniasis. By the spiracle index, the species studied are clearly divided into 2 groups. Group 1 included P. neglectus, P. perfiliewi, P. tobbi, and P. brevis having relatively small spracles which prefer more or less open areas and or the holes of small mammals and birds in the Crimea and Caucasis. Central Asian species, such P. smirnovi which inhabit in the vegetation-covered bottomlands along large rivers and the endophilic species P. longiductus, which have been related to Group 2, have the largest spiracles. P. kandelakii that are abundant in the garden-rich settlements piedmont of the Caucasus is intermediate.