picture-winged fly

Pseudoseioptera albipes is a small picture-winged fly. It occurs in eastern and central North America.

The larvae live in rotting vegetables and fruit and in feces. Adults use their distinctively patterned wings in courtship behavior. These traits are common among all picture-winged flies but are not unique to them. Beyond this, little is known of the biology of the species.

Adults are about 3 ⁄16″ (5 mm) in length.

The head is large. There is a large compound eye on each side of the head and three small simple eyes (ocelli) in a triangle on top of the head. The compound eyes do not meet at the top of the head on either sex. The upper part of the head (frons), corresponding to the forehead, is reddish, and the reddish area continues around the back of the ocellar area, which is black and shiny. The area between the face and the inner margin of the compound eye (orbital area) is broad and is covered with a fine white dust (pollinose). The face is pale yellow. The cheeks (gena) are shiny yellow. The antennae are reddish yellow and have three segments. The third segment is rounded above, and there is a large bristle (arista) on the upper side. The arista is sparsely hairy. The tube-like collection of mouthparts (proboscis) is black or brown.

The thorax is shiny and entirely black, with no pale stripes.

The legs are mostly black. On the front and muddle legs, the fourth segment (tibia) is brownish. The last part of each leg (tarsus), corresponding to the foot, is yellow.

The wings are clear with a slight yellowish tinge. The subcostal cell and the stigma are black, together making a black stripe extending from the base of the wing to the leading edge (costal margin) a little beyond the middle. There is also a dark brown or black spot at the wing tip. The R₄₊₅ cell, in the outer middle of the wing, has a short r-m cross-vein at the base, is nearly parallel sided, and is broadly open at the tip. The open area at the tip is twice as wide as the length of the r-m cross-vein. This feature distinguishes the genus Pseudoseioptera from Seioptera. The veins in the clear area are yellow, while the veins in and surrounding the black areas are black. The balancing organs (halteres) are white.

Total length: ⅛″ to 3 ⁄16″ (3 to 5 mm)

Sources

24, 29, 30, 82.

This species was formerly included in the genus Seioptera.

This species has no common name. The common name of the family Ulidiidae is picture-winged flies, and it is used here for convenience.

Alfredo Colon
8/2/2022

Location: Woodbury, MN