Type material. Syntype male of C. antatsima, labeled “ Madagascar (Sud)/Bassin du Mandraré/ Alluaud 1900 44” (DEIC, examined); Syntype female of C. antatsima var. fotsy, labeled “Mananpatra” (DEIC, examined).

Diagnosis. Length 10.5-12.5 mm. Dorsal coloration as shown in Figures 1, 2. The extensive white coloration on the elytra separates this species from sympatric species of Chaetodera and Lophyra. It is most closely related to the Madagascan C. perrieri, from which it may be distinguished by the elytral color characteristics mentioned in the key to species (the elytral white areas are broadly expanded in C. antatsima, covering much of the disc, whereas the white areas on the elytra of C. perrieri are less extensive and tend to form alternating bands with the dark ground coloration).

Notes. Horn (1934) and Olsoufieff (1934) considered this species to be a regional variant or subspecies of C. perrieri, while Jeannel (1946) treated these two taxa as separate species. Based on the specimens examined for this study, I concur with Jeannel’s assessment. The differences in color pattern between C. antatsima (Figure 1-2) and C. perrieri (Figure 3-4), although subtle, appear to be consistent among the specimens available for study. I was unable to find any specimens that represented intermediate forms that might be expected if subspecific variation was involved. I confirm that C. antatsima var. fotsy is conspecific with C. antatsima based on examination of the relevant type specimens. Specimens identified as C. antatsima var. fotsy in collections are individuals of C. antatsima in which the dark markings of the elytra are especially reduced.

Material examined. MADAGASCAR: Ambositra (1 female, DEIC); Ampandrandava (1 male, 1 female, DEIC); Beroroha (1 male, DEIC); Manampatra (1 male, 1 female, DEIC); Mandrare, I.1933 (1 female, DEIC), 1933 (1 female, DEIC); Morondava, III.1931 (1 female, DEIC); Plateau de l’Andray – Reg. d’Ambovombe (1 male, DEIC); Tamatave, 9.IV.1920 (1 female, DEIC); Tananarive (1 male, DEIC), XII.1919 (2 males, CMNH).