non-biting midge

Uncommon

May to August

Demeijerea brachialis is a small non-biting midge. It occurs in the United States and southern Canada. Based on the scarcity and wide distribution of recorded sightings, it is undoubtedly underreported, probably due to its small size and similarity in appearance to many closely related species.

The head is small and brown. The mouth parts are short and brown. The sensory appendages (palps) on the mouth have 4 segments. There are two large compound and no simple eyes (ocelli). On the upper part of the face (frons), there is a pair of minute, almost spherical bumps (tubercles) in the middle. The antennae on the male are brown and have eleven segments. The first 10 segments are very short. The last segment is very long and feather-like (plumose), with long, light brownish-yellow (ocher) hairs. The basal segment is ocher, the remainder is blackish-brown. The second and third segments are fused together, and there is a broad constriction between them that suggests a joint. On the female the antennae are shorter. They have just 5 or 6 segments, and are not plumose.

The thorax is shiny blackish-brown. It is gradually narrowed toward the center. There is a broad or very broad notch and a row of hairs in the middle.

The abdomen is yellow or light green, long, and cylindrical. Segments 2 through 5 always have a narrow brownish-black band at the base. Segment 2 is often completely brownish-black, segments 3 to 5 are sometimes partially or completely brownish-black. The segments beyond segment 5 are always completely brownish-black. Segments 3 through 6 do not have a scar-like impression at the middle of the base.

The wings are long narrow, and iridescent. They are held over the body when at rest. They do not have long hairs on the surface. The basal third is tinted yellow, there is a diffuse brown cloud in the middle third, and the remainder is clear. The wing veins are yellow at the basal third of the wing, brown beyond. There is no cross vein (m-cu) between the media vein (M) and the cubitus vein (cu). The cross vein (r-m) between the last radial vein (R₄₊₅) and M, is at a distinct oblique angle to R₄₊₅. The cu vein forks below or slightly beyond r-m. The distance between R₄₊₅ and the wingtip is equal to the distance between M and the wingtip. The ends of R₁ and R₂₊₃ are slightly but distinctly separated, not joined at the wingtip.

The legs are long, slender, and mostly ocher. The base of the first segment (coxa), the tips of the third segment (femur) and fourth segment (tibia), and the segments of last part of the leg (tarsus), corresponding to the foot, are brown. The tibia on the front leg is dark brown. At the tip there is a low, rounded scale which projects slightly beyond a similar scale on the other side. The tibia on the middle and hind legs have spurs that are modified into combs. The combs are broadly triangular, similar in shape, and separated by a distinct notch. On the middle tibia each comb has a single spine. The tarsus has five segments. The first segment is usually longer than the tibia. On the front leg the first segment is dark brown except for the basal third, which is whitish or ocher. The tarsus on the front leg has a dense beard which is longer on the outer side than the inner side. The last two segments of the tarsus on the middle and hind legs are dark brown.

Sources: 24, 29, 30, 82, 83.

Location: Woodbury, MN