The Viper's Bugloss (Hadena irregularis) is a species of moth of the family Noctuidae. It is found in Europe. The wingspan is 32–36 mm. The moth flies from July to August depending on the location. The larvae feed on Silene otites and Gypsophila species. In 1998 the United Kingdom government removed Hadena irregularis from schedule 5 (animals) of the Wildlife and Countryside Act, 1981 as it is believed to be extinct. The cause of extinction has been hypothesised to be destruction of habitat, primarily the food source, which in the United Kingdom was limited to Spanish catch-fly (Silene otites).