Overview
The Psychodidae is one of the more species-rich families of the Nematocera, with several thousand species worldwide. Although showing quite a diversity of body shapes, they are amongst the most easily recognised of nematocerans by virtue of the dense hair covering the body and wings, hence the common name 'moth flies'. Movement is characteristically jerky.
Some authors have elevated the medically significant Phlebotominae to family status, but the decision would render the remainder of the Psychodidae paraphyletic, and therefore is phylogenetically unwarranted.
The adult females of Phlebotominae, known in some parts of the world as 'sand flies', take a blood meal from vertebrate hosts. Elsewhere, especially in the non-Australian tropics and subtropics, phlebotomines may be vectors of the protozoan parasitic disease leishmaniasis.
Many psychodid larvae are fully or semi-aquatic, although many others are found in semi-terrestrial moist habitats, or in rotting wood (subfamily Trichomyiinae), compost, leaf litter, phytotelmata (
Clogmia
), etc. Those that are aquatic tend to be either hygropetric and/or tolerant of eutrophication/anoxia. After heavy rain, riparian species may be washed into the adjacent aquatic habitat. Few life histories are known from Australia.
Description
The broad wings are characteristic, with a reduced anal area, all longitudinal veins equally strongly developed, and costa running around the margin, and are held either roof-like or flat over the back. Further identificatory features include the presence of special sensilla (ascoids) on each antennal flagellomere.
Larval Psychodidae can be distinguished by the subdivision of each segment, with each subdivision dorsally sclerotised. In the subfamily Psychodinae the abdomen ends in a tubular siphon, with spiracles borne at the apex. Fringes of hairs on the siphon may allow the aquatic larva to stay at the surface of anoxic habitats.
Distribution
Worldwide, excepting Antarctica. Australian genera include widepread taxa and some endemic, evidently austral related (Gondwanan) taxa.