There are 20 species of Mantids in North America, nearly 2500 worldwide. They get their name from the way they hold their forelegs. They aren't really praying but they are an opportunistic predator, eating anything within reach, including each other. They have very powerful, downward pointing mouth parts. They can turn their triangular heads nearly 360 degrees. They have three simple eyes located between their compound eyes on the side of their heads and generally one ear located between it's thorax and abdomen. Males are typically smaller with wings that extend beyond their thorax. The females wings are shorter and colorful. Males are more adept at flight than the female. 
A mantid's color gives them the ability to blend in with the habitat in which they hunt. Some hunt in trees and shrubs while others hunt on the ground. Females require more food and are often seen near flowers which attract a variety of prey. The weave back and forth and strike quickly to grab an insect, small reptile or a finger. They often become prey to birds, spiders and humans. They are not harmful to humans and will only bite in defense. The spines on their forelegs can hurt a bit if they grab a finger.
During mating the female will, occasionally, attack her mate and eat him as he approaches her or during or after mating. In the fall the female will attach her egg case to a rock, a wall or another hard surface. She will even attach it to a plant stem or under a leaf. She will stay near to protect the egg case from predators. The egg case will hatch in about three weeks. She will die soon after. When the young hatch they will hunt whatever is nearby. If food is not readily available they will devour each other.Mantids molt six to nine times before adulthood. The young mantid has no ear but will begin forming one by the third molt. By the sixth molt it's ear, which is located in the middle of its thorax, is fully developed. Mantids can get very large and are quite beneficial in gardens as they eat any manner of insects.
