Egg sac with ridges?

Asked July 12, 2020, 1:36 AM EDT

I have found several of these in my garage. I can't figure out what they're from. They have a tough outer part and seem to be malleable. It looks flat in the pictures but just seem to be deflated oblong sacs. The ridges go all the way around.

Multnomah County Oregon

1 Response

Depending upon its size, that may be the pupal case (the non-feeding life stage) of a Little House Fly, Fannia canicularis.

To determine if that is so, put several in a clear container with a porous lid of perhaps a paper towel held in place with a rubber band. Set it on the counter where you'll see it every day, but not n the sun. Then wait to see what, if anything, happens next, and send an image of what you see.