Antherina suraka (Boisduval, 1833) (Lepidoptera: Saturniidae) is endemic to Madagascar and the Comoros. Investigations in the 1950s and 1960s found slight morphological differences between typical populations and those from dry areas of Madagascar, a “form”—australis—that was not given formal taxonomic recognition. In the Comoros, A. suraka is represented by a distinct subspecies, A. suraka comoranaViette 1965. The goal of this study was to increase insight into the biological significance of intraspecific variation within A. suraka by studying male genitalia and flight times, and DNA barcode sequences. We also tested whether genetic divergence between sites was correlated with geographic distances or host use. No differences in male genitalia were found. Moths from western Madagascar were found typically flying 2 h earlier in the evening than eastern moths. A Bayesian phylogeny derived from the mtDNA barcode sequences supported: 1) a western clade comprising the “australis” populations, 2) a clade composed mainly of specimens from eastern/central Madagascar, and 3) a third unit in the Comoros representing the subspecies comorana. While these results could be viewed as supporting the existence of more than one species within A. suraka, recovery of eastern haplotypes in western areas, and the presence of genetic isolation by distance, weaken the case for taxonomic division: more genetic data are needed. Regardless of exactly how the systematic status of this species is resolved, the presence of three distinct populations of A. suraka living in different habitats illustrates the importance of protecting forests in this biodiversity hotspot.