Tethininae
Tethininae, formally the family Tethinidae is a paraphyletic group of tiny drab-coloured or grey Acalyptratae flies. There are over 115 species in 7 genera known from all zoogeographic regions. They are inconspicuous flies which are still poorly known in some remote, huge, tropical areas (e.g. South America). Natural history. Tethininae are found in maritime, often littoral habitats. The adults are sometimes abundant in rotting seaweed. A few species occur inland, in association with alkaline habitats in arid zones. Except for the subantarctic genera "Apetaenus" and "Listriomastax", little is known about the immature stages of the family, although presumably  most are associated with rotting seaweed. Workers in dipterology which are unfamiliar with tethinids often associate these flies with the presence of seashores, particularly sandy beaches and coastal lagoons. This is true for most strictly thalassophilous species, which occur on dunes, sandy soil and wrack heaps stranded on the beach. However, many entomologists often ignore or simply overlook the fact that populations of certain species also inhabit biotopes situated far off from sea littorals, sometimes several hundreds of kilometres inland, and are almost always closely dependent on the proximity of continental saline environments. It is well known that most species , if not all, belonging to the subfamily Pelomyiinae are not thalassophilous flies, but are almost exclusively found inland, associated with meadows, mountain passes, forests, areas and waters polluted by rotting waste, industrial emissions or debris of slaughterhouses and poultry farms (sites of salt accumulation and enrichment), as well as desert oases. However, this is not infrequent in various species of the genus Tethina, too. Subfamily Description. See