The lengths of the male genital filaments and female spermathecal ducts were measured in phlebotomine sand flies of the Lutzomyia intermedia
species complex and the ratios between these characters calculated. Ratios for L. intermedia
s. s. from Northeast vs Southeast Brazil (Espírito Santo and Minas Gerais), Espírito Santo/Minas Gerais vs Rio de Janeiro/São Paulo and L. intermedia
vs L. neivai
were significantly different at P < 0.1, 0.05 and 0.01 respectively when compared using ANOVA. The spermathecal ducts and genital filaments of L. intermedia
were significantly longer than those of L. neivai
(P < 0.01) and could be used to differentiate these species. The taxonomic and biological significance of these differences is discussed.