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The dispersal and survival of the phlebotomines Nyssomyia intermedia and Nyssomyia neivai (both implicated as vectors of the cutaneous leishmaniasis agent) in an endemic area was investigated using a capture-mark-release technique in five experiments from August-December 2003 in municipality of Iporanga, state of São Paulo, Brazil. A total of 1,749 males and 1,262 females of Ny. intermedia and 915 males and 411 females of Ny. neivai were marked and released during the five experiments. Recapture attempts were made using automatic light traps, aspiration in natural resting places and domestic animal shelters and Shannon traps. A total of 153 specimens (3.48%) were recaptured: 2.59% (78/3,011) for Ny. intermedia and 5.35% (71/1,326) for Ny. neivai. Both species were recaptured up to 144 h post-release, with the larger part of them recaptured within 48 h. The median dispersion distances for Ny. intermedia and Ny. neivai, respectively, were 109 m and 100 m. The greatest dispersal range of Ny. intermedia was 180 m, while for Ny. neivai one female was recaptured in a pasture at 250 m and another in a pigsty at 520 m, showing a tendency to disperse to more open areas. The daily survival rates calculated based on regressions of the numbers of marked insects recaptured on the six successive days after release were 0.746 for males and 0.575 for females of Ny. intermedia and 0.649 for both sexes of Ny. neivai. The size of the populations in the five months ranged from 8,332-725,085 for Ny. intermedia males, 2,193-104,490 for Ny. intermedia females, 1,687-350,122 for Ny. neivai males and 254-49,705 for Ny. neivai females.

The capture of a new species of the subgenus Migonemyia Galati, 1995 (Diptera, Psychodidae, Phlebotominae), Migonemyia vaniae sp. nov. in the Ribeira Valley, state of São Paulo, Brazil, together with the other two species: Mg. migonei (França, 1920) and Mg. rabelloi (Galati & Gomes, 1992) lead us to review this subgenus. The new species was described and illustrated. The genitalia of the two other species were also illustrated and some genital characteristics (number of setae on the gonocoxite tuft, ejaculatory ducts and pump and ducts/pump ratio; and number of setae on the tergite VIII of the females) considered important to differentiate the three species, including five populations of Mg. migonei (from Northeastern, Southeastern, and Southern Brazilian regions and of Peru) were submitted to variance analyses. The Mg. migonei population of Northeastern Brazilian region showed distinct smaller values (P < 0.05) than the other Brazilian populations studied as regarding these characteristics. The capture of both sexes of these three species in sympatry confirms the association between the sexes of Mg. rabelloi, recognised as doubtful when this species was originally described. Identification keys for male and female of the three species are presented.