Mouthparts of the Biting and Blood-sucking Type in Tanyderidae and Chironomidae (Diptera)

Abstract

IN the Diptera fully mandibulate mouthparts adapted to penetrate the skin and ingest the body fluids of the host have been recognized in only seven families, the Culicidae (mosquitoes), Simuliidae (black flies), Ceratopogonidae (biting midges), Psychodidae (sandflies), Blepharoceridae, Tabanidae (including horseflies) and Rhagionidae^1,2. The mouthparts of these forms are co-adapted and specialized in relation to the mode of feeding, but morphologists have shown that all the main elements of the typical insect mouthparts are present and show in particular a rather close resemblance to those of certain members of the ancient order Mecoptera^1,3. In other Diptera, however, the mandibles have not been recognized (except in two groups adjacent to the Culicidae, and another near the Tabanidae, where they are present in a non-functional form); and although some can take blood in various ways, the majority are restricted to already exposed liquids, such as decaying organic material and nectar. The families listed do not form a single compact group but seem to represent relatively primitive stocks on several lines of descent, and this is recognized by their rather scattered placement in most classifications⁴. It has been proposed therefore that they represent the primitive condition, surviving in several different stocks but lost by reduction in most Diptera².