From several feet away it looked like a bit of leaf stuck to the window. I got closer and noticed legs and a head. It was only 2 inches long. I hurried for the camera and got these two views looking through the glass to the outside. The purple barberry bush gave a dark background for contrast.
Late last fall, we noticed a mantis egg case on this spirea bush next to the front sidewalk.
I moved the empty egg case in order to photograph it. The species is likely the Chinese Mantis (Tenodera sinensis). They were introduced to the U.S. in 1896. This article said cases can contain up to 200 mantis eggs. This case is about 1.5 inches tall. We looked at it each time I walked by the bush in hopes of seeing them hatch. No luck. About two weeks ago we noticed some very small young ones on the bush. An ant was even trying to drag a dead one along the sidewalk.
When they emerge from the egg case (ootheca), they descend on a fine silk-like fiber. This short video shows a batch emerging. It is important that they quickly move to a safe place. The mantis is a carnivore. The young will eat each other.
Recently, we returned from an early morning walk in the cool air. The sun was shining brightly on the warm front door as we entered the house. Something moved on the floor. There was a mantis walking along. It apparently came in when we opened the door. We safely delivered it back outside into the bushes.