green soldier fly

not listed

NNR - Unranked

not listed

Green soldier fly is a large, wasp-like, soldier fly. It occurs in southern Canada, the United States, and northern Mexico. The larvae are aquatic, and adults are always found near water.

Adults are ⅜″ to ⅝″ (10 to 15 mm) in length.

On the female, the head is more or less hemispherical. There are two large compound eyes on the side of the head and three small but prominent simple eyes (ocelli) in a triangle at the top of the head. The compound eyes are widely separated at the top of the head. The face is green. The forehead (frons) is green with a wavy black horizontal line above the antennae bases. The top of the head (vertex) is green except for a large, oval, black area around the ocelli. The antennae are long (for a fly) and are inserted just above the middle of the face. They have three segments. The first two segments are reddish-brown, the third segment is black, at least at the tip, and is divided into five ring-like segments (annulated). It does not have a bristle-like appendage (arista).

The thorax is black above and green on the sides, with two green spots in the middle. This is the feature that gives the fly the species epithet binotatus, meaning “twice-marked”. The spots are highly variable in size, from elongate and almost reaching the rear margin, to round and tiny. On some individuals the spots are inconspicuous or missing. The exoskeletal plate between the wing bases (scutellum) is green and has two yellowish spines.

The abdomen is green with a black band at the base of each segment. The width of the bands is variable, sometimes dilated in the middle and meeting the band on an adjacent segment. The underside of the abdomen is entirely green.

The legs are moderately long and mostly reddish-brown. On each leg the base of the third segment (femur) and the base of the fourth segment (tibia) are yellow.

The wings are clear with brownish-yellow veins. Three veins of equal length extend from the discal cell. There are five distinct cells at the outer part of the wing. The radial vein (R) has two branches, and they are crowded in the front of the wing. The posterior branch (Rs) has three branches. The posterior branch of Rs (R₅) ends at the margin before the wing tip. The anal cell is longer than the second basal cell and is closed near the wing tip.

On the male, the compound eyes meet at the top of the head. The face is entirely green with no black markings. On the front legs, the tip of the femur, the base of the tibia, and the last part of the leg (tarsus), corresponding to the foot, are black.

Total length: ⅜″ to ⅝″ (10 to 15 mm)

Larvae live in water. Adults are found on flowers.

Sources

7, 29, 30, 82, 83.

Infraorder
Orthorrhapha was historically one of two infraorders of Brachycera, a suborder of Diptera. However, Brachycera did not contain all of the descendants of the last common ancestor (paraphyletic). It was split into five extant (still existing) and one extinct infraorder. Orthorrhapha is now considered obsolete and has not been used in decades, but it persists in printed literature and on some online sources. A recent revision of the order Diptera (Pope, et al., 2011) revived the name Orthorrhapha, but this has not been widely accepted.

Species group
BugGuide.net treats Hedriodiscus binotatus, Hedriodiscus truquii, and Hedriodiscus varipes as the Hedriodiscus binotatus species group. This is an informal group not recognized outside of BugGuide.net.

Hedriodiscus binotatus group soldier fly with brown and green abdomen

Hedriodiscus binotatus group, soldier fly with green abdomen and brown markings, on Canada wild rye grass. Barnes Prairie, Racine County, WI, July 16, 2021.

Location: Barnes Prairie, Racine Co., WI

Hedriodiscus binotatus group, soldier fly with green abdomen and brown markings, on Canada wild rye grass. Barnes Prairie, Racine County, WI, July 16, 2021.