Chalcid Mimicking Fly

Description:

What I had first thought to be a Chalcid Wasp with its enlarged hind femora turned out to to be a small fly. It has a narrowed waist, pictured wings, bright red eyes with stripes, a metallic green abdomen on the dorsal side (5th picture) and prominent halters. The hind femora are enlarged, banded with orange and have teeth along the inner edge. I can't imagine what a non-predatory fly does with those strong spiny hind legs. It is about 4 mm long, the actual size compared to my thumb nail is visible in the last picture. The wing pattern puts it in the genus Richardia of the small Family Richardiidae. They are usually saprophytic as adults, and it does seem to have sponging mouthparts. They are not well studied nor often seen. See the spotting by Sckel of a red Richardiid from Brazil that mimics an ant (http://www.projectnoah.org/spottings/323...).

Habitat:

Found on a bush along the highway between San Cristobal de Las Casas and Tuxtla Gutierrez, km 18.5 at 1164 meters.

Notes:

http://www.boldsystems.org/index.php/Tax... https://en.wikipedia.org/wiki/Richardiid... http://www.pbase.com/image/124473432 http://naturecloseups.com/posts/subjects... http://www.drawwing.org/insects/diptera/...