bee-mimic robber flies

Laphria sericea and Laphria atkis are two very similar, small to medium-sized, robber flies. Both species occur in the eastern half of the United States and southern Canada. They cannot be told apart in most photos, only in those that clearly show the genital bulb of the male. A third undescribed species has been found that is also basically identical in general appearance. For this reason, the three species are sometimes treated as a species complex called Laphria sericea complex.

Cedar Creek Ecosystem Science Reserve has both Laphria sericea (as Cryptocornutus sericea) and Laphria atkis (as Hirtochona atkis) on their Checklist of Minnesota Insects, but it has a record for only Laphria atkis.

Adults are found from May to July in woodland edges and openings. The larvae live in the soil or in rotting wood, where they prey on the larvae of other insects.

Adults are black, slender, and ½″ to 1″ (13 to 25 mm) in length.

There is a dense mustache of long, stiff bristles (mystax) on the face immediately above the mouth. The mystax is black. On the lower part of the face there is a cluster of forward-directed bristles (a “beard”). The beard is whitish on the female, tawny on the male. On the female there are whitish hairs on the first segment (coxa) of each leg, downward curved whitish hairs on the face, and a tuft of whitish hairs below each wing base. On the male, these hairs are tawny.

The upper side of the thorax and abdomen have yellowish-golden to brilliant red hair. On the male, at the rear margin of the sixth abdominal segment, there are two black, well-defined projections (forceps).

The legs are stout and black. They are covered with long black hair mixed with white hair.

The wings are clear and are tinted blackish.

Sources

24, 27, 29, 30, 82, 83.

The superfamily Asiloidea was formerly placed in Orthorrhapha, 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.

I enjoy taking pics of Robber Flies. This is a relatively big one and maybe a bee-mimicking one.

Location: Woodbury, MN

I enjoy taking pics of Robber Flies. This is a relatively big one and maybe a bee-mimicking one.