| Abstract: | Morphological variations in 10 habitus characters of adult Heizmannia greenii (Theobald) collected from the eastern, central and southern regions of Sri Lanka were examined and quantified. Pale-scaled areas conforming to those of the type form of the species were seen in 67–100 and 74–93% of eastern and central region specimens respectively. By contrast, 76–100% of specimens from the southern region had the the same areas completely or nearly completely covered with dark scales. Specimens with individual characters and character combinations intermediate between the extreme ‘pale’ and ‘dark’ forms were observed. All of these variants were inseparable from typical Hz. greenii on the basis of male genitalia characters, and larval and pupal morphometrics and chaetotaxy. It is likely that the variability observed in adult ornamentation is the reason for the confusion that has existed in the literature regarding the identity and distribution of Hz. greenii. Such extreme variability within a species raises questions regarding the stability of taxonomic characters used to separate species within the genus. |
