Gold Triangle Hypsopygia costalis
The Gold Triangle is a beautiful purple and yellow moth. When resting it is in one of two characteristic positions. When just resting and after being disturbed it rests in the arrow head position. When deep in rest the wings are completely spread out in a pose rather like a Geometer's. It is similar in colouring to the Mint Moth, but the main difference is the broad yellow fringe of the Gold Triangle. And this also makes it an unmistakable species. Reaching a wingspan of 18 to 22mm it is bigger than the Mint Moth is.
The eggs hatch in September. The larvae eat until half grown, then hibernate. In spring they awake and complete their development. Pupation usually takes place in May or June in a firm oval cocoon. The caterpillars feed on dried vegetable materials and may be found in old mamal's nests (like a rabbit's or a fox's), old bird's nests, hay stacks, hen houses and thatch.
The Gold Triangle is on the wing in July and August. Contrary to the similar Mint Moth it flies by night only. Is attracted to both light and sugar. Found at rest during the day in thickets and bushes, but in and on buildings as well, especially sheds, stables and hen houses. In Britain this is a locally common species in Southern England only. In continental Europe south of Britain on the wing from May to October. Als common in Northern America and often even abundant.
In Northern America this moth is better known as the Clover Hayworm Moth.