MORPHOLOGICAL VARIABILITY OF ADULT HEIZMANNIA-GREENII (DIPTERA, CULICIDAE) FROM SRI-LANKA

Morphological variations in 10 habitus characters of adult Heizmannia greenii (Theobald) collected from the eastern, central and southern re gions of Sri Lanka were examined and quantified. Pale-scaled areas con forming to those of the type form of the species were seen in 67-1 00 and 74-93 % of eastern and central region specimens respectively. By c ontrast, 76-100% of specimens from the southern region had the the sam e areas completely or nearly completely covered with dark scales. Spec imens with individual characters and character combinations intermedia te between the extreme 'pale' and 'dark' forms were observed. All of t hese variants were inseparable from typical Hz. greenii on the basis o f male genitalia characters, and larval and pupal morphometrics and ch aetotaxy. It is likely that the variability observed in adult ornament ation is the reason for the confusion that has existed in the literatu re regarding the identity and distribution of Hz. greenii. Such extrem e variability within a species raises questions regarding the stabilit y of taxonomic characters used to separate species within the genus.