Yeah, I know. I had a discussion with Eric a couple of years ago about how you can have a brown green-lacewing but all brown lacewings are always brown :-O ....I'm feeling a little dizzy....

If you look at some of these brown green lacewings in your pictures they do have a bit of green in them. I've been taught that often times when they begin to get ready for overwintering they turn brown. I wonder if its some chemical process in the insects that make it impossible to stay green when they're too cold. Some reptiles do the same, change colors at different temperatures.

Apparently Chrysoperla carnea is one of the species that will overwinter as freshly hatched adults, others usually overwinter as pupae.

Also, you are not the first person this fall to post pictures of a swarm but I've never really heard of it before. Interesting...