And the egg hatches...

A few weeks ago, Carolyn and I found a little unusual packet hanging on one of our trees in the backyard. It was about an inch long and a half inch in diameter. I tried to take a picture but the camera focused on the tile beneath the bottle. We assumed it was a chrysalis for some moth or butterfly. To find out what kind it was, we clipped off the small limb the pod was hanging onto and placed it carefully in a one quart jar which we capped and put on the kitchen counter. I thought about punching holes in the lid but decided that it was loose enough that the pod would get enough air as is.

And that was pretty much it until this morning. We had just left it alone except when we had to move the bottle to use that part of the counter. This morning, I reached to move the bottle and saw that the pod was a little ragged looking, sort of like a knitted sweater coming undone. You can see it at the top of this picture. Had we hatched a butterfly? No. Nor was it a moth. It was dozens of little green bugs about a quarter inch long and looking vaguely like miniature praying mantises. Talk about creepy.

I'd like to find out what the little fellows are and whether they're harmful or beneficial for our backyard. Can anyone identify these?