The flightless females, which are often encountered while wandering on the ground, especially resemble ants. Two large ones include the Satan's, one of them is black with a yellowish-white abdomen and the other is red and black. They are all in the family Mutillidae.
Size appears to depend upon size of host used during development.
Velvet ants look like miniature walking cotton balls. Red, orange, yellow, black or white bristle-like hairs, known as setae, cover the entire body. Males have wings but no stingers, while females have stingers but lack wings. Over 150 species of velvet ants occur throughout the United States, southern Canada and Mexico, although this is a rough number. Only about one third of those species are known from both sexes, while another one third are known from males only, and the final one third, from females only.