A series of different-looking tiger moths was collected at pyrrolizidine alkaloid baits in the daytime in Peru. They proved to be variants of a new genus, Vanewrightia gen. nov., and a new species, Vanewrightia kiesela sp. nov., both described here. This species presents a striking example of extensive intraspecific variation within a population. Its discovery demonstrates the importance of sampling moths by means other than collecting with light, of studying patterns of wing undersides, and of the value of barcoding. Specimens found in collections considered here potentially to represent further species of the new genus are documented and discussed; Vanewrightia subflavescens (Kaye, 1911) comb. nov., and Vanewrightia patawaensis (Cerda, 2017) comb. nov. are established; we propose Epidesma parva (Rothschild, 1912) as a junior synonym of E. aurimacula (Schaus, 1905). The newly recognized intraspecific variation greatly challenges delimitation of morphospecies and uncovers uncertainties in the taxonomy of Epidesma Hübner, [1819]. The occurrence of an oblique forewing band in many Lepidoptera and the stunning similarity in overall appearance of variants of Vanewrightia with unrelated taxa, in particular notodontid moths (Josiini) and Chamaelimnas C. & R. Felder, [1885] butterflies (Riodinidae), are discussed in the context of mimicry and crypsis, and some perspectives for further research are suggested.