Close up of legs of an adolescent Chinese mantis Tenodera sinensis. The spikes are used to impale prey as it is grasped in the mantis磗 powerful forelegs. The Chinese mantis is the largest mantis in the U.S. with adult females reaching 100 mm in length. They were introduced in the U.S. in 1895 to control insect pests. Today they are found throughout the Northeast and elsewhere in the world.