Scenopinidae

Scenopinidae can be distinguished from related families Therevidae and Bombyliidae by wing venation: the media has only two or three branches (reduced compared to Therevidae), and the radial system is simpler than in Bombyliidae. In most of the family, the costa stops short of the wing apex, ending at the termination of R5 or M1 (except in Caenotus, where costa extends the full margin). The radius divides into four branches with R2+3 undivided; the entire radial system is positioned in the anterior half of the wing. R4 terminates on the costal margin, while R5 terminates before or at the wing apex. M1 is always present; M2 is absent in most Scenopininae but present in Proratinae, Cyrtosarthe, and Caenotus; M3 is absent throughout the family; M4 is always present. The marginal cell is very narrow and opens on the costal margin, as does the submarginal cell. The discal cell is pentagonal (quadrangular in Scenopininae).

Adults are small insects, usually with body length not exceeding 5 mm. The body is glabrous or slightly hairy with blackish coloration. The head has three ocelli. Male antennae are holoptic in most species, while females are dichoptic. Antennae are pendulous with three segments: two short basal segments and an elongated third segment with a non-annulated flagellum. Mouthparts are of the sucking type with a short labrum (proboscis) bearing a fleshy apex; maxillary palps are one- or two-segmented. The thorax is moderately convex, with mesoscutal bristles present in Proratinae. Legs are short and lack arolia and empodia. Wings overlap on the abdomen at rest. The abdomen is large and cylindrical or flattened, with seven visible segments in males and eight in females.

Larvae typically inhabit sandy soils of arid environments or dry litter. They also occur in wood, decaying organic substrates, burrows and nests of mammals and birds, and occasionally in domestic environments. In Australia, the family is concentrated in hotter, more arid regions including northern Queensland, Northern Territory, and Western Australia. Adults are frequently observed on windows in buildings.

Worldwide distribution. The Nearctic realm currently holds the most described species, though this likely reflects sampling intensity rather than actual diversity. Documented occurrences include North America, South America (Argentina, Chile, Uruguay, Peru), Australia, Europe (including Finland, Sweden, Norway, Denmark), Africa, and Asia. Two species (Scenopinus fenestralis and S. glabrifrons) are cosmopolitan, associated with human trade and movement of goods.

Larvae are predatory, feeding on other soil arthropods and terrestrial arthropods. Specific prey records include stored-grain pests, moth larvae (clothing moths, food moths), beetle larvae, termites, dust mites, and fleas. Larvae may prey on other insect larvae including therevid larvae in soil. Adults have sponging mouthparts and feed on nectar and honeydew from open flowers.

Complete metamorphosis with egg, larval, pupal, and adult stages. Larval biology is poorly known for most species. Larvae have been found in association with stored-grain pests, in nests of birds and rodents, in beetle larva burrows in trees and shrubs, and with therevid larvae in soil. Specific details on egg deposition sites, pupation, and generation time are not well documented.

Adults are commonly found at windows in buildings, hence the common name 'window flies.' Larvae are predatory across all habitats where they occur. Some species show synanthropic tendencies, with larvae adapting to domestic environments to prey on household pests including clothing moths, food pests, termites, dust mites, and fleas. The two cosmopolitan species have spread through association with human commerce and trade goods.

Larvae function as predators of other arthropods in soil and decaying organic matter ecosystems. In domestic settings, some species provide biological control of household pests including moths, beetles, termites, mites, and fleas. Adults may contribute to pollination through nectar feeding at open flowers.

Some species are beneficial in domestic environments, where larvae prey on pest insects including clothing moths, food storage pests, termites, dust mites, and fleas. The common name 'window flies' reflects their habit of accumulating at windows in buildings. Two cosmopolitan species (Scenopinus fenestralis and S. glabrifrons) have spread globally through human trade, though they are not considered significant pests. The family has been studied for its potential in biological control of stored-product and household pests.

• TherevidaeSimilar overall morphology and shared infraorder Asilomorpha; distinguished by Scenopinidae having reduced media branches (2-3 vs. more in Therevidae) and different wing venation patterns
• BombyliidaeRelated families within Asilomorpha with similar body plans; Scenopinidae have simpler radial wing venation and typically shorter costa not reaching wing apex

• Diptera
• predatory larvae
• synanthropic
• window flies
• arid habitat
• cosmopolitan species
• biological control
• Asilomorpha

• BugGuide
• Wikipedia
• GBIF taxonomy match
• NCBI Taxonomy
• Catalogue of Life
• Publications | Entomology Research Museum
• A review of Australian Scenopinidae (Diptera)
• EIGHTEEN NEW SPECIES OF AUSTRALIAN SCENOPINIDAE (DIPTERA)†
• Occurrence of the Scenopinidae Family in animal droppings (Insecta: Diptera)
• The genus Heteromphrale Kröber, 1937 (Diptera; Scenopinidae) in Peru, with the description of a new species El género Heteromphrale Kröber, 1937 (Diptera; Scenopinidae) en Perú, con la descripción de una especie nueva
• The genome sequence of a window fly, Scenopinus jerei Pohjoismäki & Haarto, 2021 (Diptera: Scenopinidae).
• Scenopinusjerei, a new species of window fly (Diptera, Scenopinidae) from Finland.