This fairly large robber fly has a neat, “trim” mystax, or “mustache.”

This beautiful creature is a large robber fly, one of the Hanging Thieves, likely Diogmites basalis. I took a picture of this presumably ovipositing female who (out of the camera’s purview) was digging her abdomen into a sandy or gravelly part of my backyard. She is sporting quite the handsome mystax (i.e. the white mustache) that serves as protection from counterattacking prey, such as stinging Hymenoptera. A print of this photograph is featured in my Bugs in the Library exhibition at the North Adams Public Library.

Unbeknownst to whom? Perhaps both the large robber fly as well as the sawfly larva curled up inside the leaf are not aware of each other.

[Please note: Second photo features a different individual.]