We did it!
Has an answer: Marsh Fly, Snail-Killing Fly, Tetanocera ferruginea
It was a thrill to follow the suggestions of helpful blogging buddies… your suggestions ultimately led to the three keys that unlocked the mystery:
- Biodiversity in Focus– a blog authored by an entomology graduate student and nature photographer
- Bug Guide.net
- Encyclopedia of Life.org
“What I think you’ve found is a species of marsh or snail-killing fly in the family Sciomyzidae.” Morgan D. Jackson
And what an interesting insect this one turned out to be…
Marsh flies are generally slender, yellowish or brownish, 1/4 – 1/2″ long. They have fairly prominent eyes, prominent forward-pointing antennae, and bristles on the femora (upper hind leg). The wings are mottled with various light brown markings according to species.
Marsh fly larvae prey on or become parasites of slugs & snails.
Habitat: Near ponds, streams, marshes.
Range: Throughout North America.
Food: Adults drink dew, nectar, and tree sap.
Location: Glencoe Swale, Hillsboro, Oregon