Multillidae or velvet ants, also known as cow killers, are not actually ants, but a type of wasp. They get their name from the hair that grows on their back. The hair ranges from red and black to completely white. Their shell is very tough, providing protection against wasp and bee stings. The males have wings, but the females are completely wingless.
The earliest-known velvet ants come from 25-40 million year old amber from the Dominican Republic.