longlegged flies

Condylostylus caudatus is a species complex of six very similar longlegged flies. It occurs throughout the United States and southern Canada. Adults are found in woodlands and meadows near streams and swamps. They prey on smaller insects. Larvae live in soil or under bark and are seldom seen. They prey on small invertebrates.

Adults are slender. The head, eyes, thorax, and abdomen are shiny and metallic green with a little to a lot of copper coloration. Females in the complex cannot be identified to the species level from photos.

The head is broader than the thorax. There are two large compound eyes on the sides of the head and three small simple eyes (ocelli) in a triangle on top of the head. The compound eyes are bare, with no hairs. They do not meet at the top of the head on either sex. The antennae are black and short, shorter than the head. They have just three segments. The third segment is not ringed. There is a stiff, forward-pointing bristle (arista) on the upper side of the third segment. The arista is slender, very long, and bare, not feather-like (plumose). The combined protruding mouthparts (proboscis) is short and is modified for piercing. On males, there is usually white hair on the face.

The thorax is large and has three segments. The upper (dorsal) plates, from front to rear, are the prescutum, scutum, and scutellum. The prescutum and the scutum are not differentiated – there is no groove between them.

The abdomen is long. On the male, it is narrow, and there is a conspicuous tail of long hairs at the tip. The genitalia are large, conspicuous, and folded under the abdomen. On the female, the abdomen is more rounded, is tapered, and there are no long hairs at the tip.

On males, the wings are clear and unmarked. The branch on the media (M) vein is at a right angle. Vein M1 is gradually curved, more gradually than in other Condylostylus species. The radial sector (Rs) vein has two branches and is slightly swollen at the fork. The radial-media (r-m) cross vein, a short vein between the radius and media veins, is in the basal quarter of the wing. The anal cell is small.

The legs are long. On the male, the third leg segment (femur) is usually mostly black, yellow just at the tip, but it is sometimes entirely yellow. On the female, the femur is always entirely yellow. On the male, the fourth segment (tibia) on the front and middle legs is entirely yellow. On the hind legs, the tibia is mostly yellow, darkened just at the tip. On most species in this complex, there is a very long bristle at the tip of the tibia on the middle legs of the male. On the middle legs of the female, there is usually a set of bristles at the tip and a strong bristle at about the one-third point of the tibia. The last part of each leg (tarsus), corresponding to the foot, has five segments. On the male, the first tarsal segment on the middle legs usually has a dense row of curved bristles.

Woodlands and meadows near streams and swamps

Adults perch on broad leaves. Males wave their front legs in courtship display.

The larva pupates in the soil in a cocoon fashioned from soil.

Sources

29, 30, 82, 83.

Condylostylus cf. caudatus courthsip
Entomofauna

Complex condylostylus caudatus, Nova Scotia. July 2, 2024
js6w3

lengthy caudatus hover flight
Keith Short

Alfredo Colon
7/7/2024

Location: Albany, NY

Alfredo Colon
8/4/2022

Location: Albany, NY