The Therevidae are a family of flies of the superfamily Asiloidea commonly known as stiletto flies. The family contains about 1,600 described species worldwide, most diverse in arid and semiarid regions with sandy soils. The larvae are predators of insect larvae in soil. Description Adult Therevidae are small- to medium-sized with a body length of 2.4 to 18 mm and a hairy integument. The coloration ranges from shades of yellow to black, but commonly the background colour is masked by the tomentum. The compound eyes are generally larger in males, which in many species are actually holoptic. Females have well-developed compound eyes, but are clearly dichoptic. There are three ocelli. The antennae are relatively short. The scape is elongated, the pedicel very short, and the first flagellomere is conical and elongated, the apex bearing a compound stylus with one to three segments. The scape and pedicel are pubescent; In contrast to the related and confusingly similar family Asilidae, the labium in the Therevidae is not a piercing, predatory organ, but ends in two fleshy labella adapted to the sucking of liquid foods. Another difference is that, though Therevidae commonly have fluffy setae above the mouthparts, the setae are not stiff bristles like the protective chaetae comprising the mystax of most species of Asilidae. Furthermore, in the Asilidae the depression on the vertex between the eyes, tends to be more obvious than in the Therevidae. The thorax is broad and moderately convex, with long bristles (macrotrichae). The legs are long and slender, with femora and tibiae bearing bristles; the tibiae are without apical spurs and the tarsi are provided with empodia or without the median pretarsal. The wings are well developed, hyaline or opaque, often with pigmentation of the veins located at the termination of the transverse and longitudinal veins. The abdomen is tapered and elongated, typically 3 to 4 times as long as its broadest width when not extended for activities such as oviposition. Eight abdominal segments (uriti) are externally visible. The wing venation is relatively complex but without a particular conformation to distinguish the Therevidae from other families of Asiloidea. The radius is divided into four branches, with R 2 +3 undivided. The branch R 4 is long and winding and reaches the costal margin, the branch R 5 terminates on the posterior border, so the second submarginal cell is open at the apex of the wing. The media