malaeng chi pa-khao (แมลงชีปะขาว)

Thai for ‘Mayfly’ or ‘Dayfly’, i.e. a family of aquatic insects the belong to the order Ephemeroptera, which is part of the Palaeoptera, an ancient group of insects that also includes dragonflies (fig.) and damselflies (fig.). Akin to the latter groups, mayflies also spend most of their lives as nymphs in fresh water, until they hatch into a fully-winged, terrestrial adult. Like dragonflies and damselflies, mayflies moult with wings that −while at rest− do not fold flat over the abdomen, but instead are held upright, like those of most butterflies (fig.). At the posterior part of the abdomen, both with the nymphs and adutlss, are three distinctive long, thread-like tails. Mayflies get their name for the fact that they hatch in large numbers from spring to autumn, though not necessarily in May. They are unique among insects, in that they moult a second time after already having acquired functional wings. The first stage after moulting into a fully-winged terrestrial adult is knows as subimago, while the final stage is called imago. Though they physically resemble each other, the subimago is usually sexually immature and the wings are murky and fringed with tiny hairs, whereas with in the final instar (stage of moulting), the wings are clear and transparent, and the Mayfly is now ready for mating. However, this final instar usually lives for only a very short time and has consequently been nicknamed Dayfly. At this stage, its flight is often erratical and it easily falls into the water, where it becomes an easy food source to many fish. The final Mayfly instar is also used by fly fishermen, who refer to it as a dun. In English also commonly known as Shadflies and in Thai these flying insects may also commonly be referred to by the English corresponding term mayflies (เมย์ฟลายส์). See List of Thai Insect Names. See also WILDLIFE PICTURES. 回