Spongillafly (Sisyridae)

A couple weeks ago about the middle of November I took a walk along the Shenandoah River on my way home from grocery shopping. I had my camera with me so of course I took it along. I was looking for spider egg sacs for my post on those interesting tiny things so I was looking very closely at the trees and rocks. To my surprise I found this interesting web structure. It is about the size of a quater.

At first I thought it was a spider egg case and I had seen a photo of it on the cover of my current favorite book, Tracks and Sign of Insects by Charley Eiseman and Noah Charney. If you are a naturalist and don’t have this book you should put it on your Christmas list this year, you won’t be disappointed. Anyway I began taking photos like crazy.

When I returned home and looked it up I realized it was a Spongillafly in the family Sisridae. They are related to lacewings but to my mind the adult looks more like a caddisfly. The larvae live in the stream and feed on fresh water sponges. I was hoping we had sponges in the river but I have never seen them. Anyway the larvae move up onto the side of the bank when they are ready to pupate. So this isn’t an egg sac after all, it is a pupa. This larva crawled out of the water and up onto the underside of this rock where it built this elaborate cocoon.

Find more interesting creatures at Camera Critter.