The wingless females actively search for hosts on which to deposit eggs. The host is attacked after its cocoon has been spun, or the puparium formed. Eggs hatch and young larvae feed on the host, devouring it. After feeding, the velvet ant larva spins its own cocoon within that of its host. Overwintering occurs as the prepupal stage inside the host's cocoon.
Developmental times vary between species and in response to various environmental conditions.
Upon emerging as adults, winged males search for mates. The wingless females attract males of their own species using specific sound produced by a rasping structure located between their second and third abdominal segments. Mating lasts for only a few seconds. Males not searching for females are often found visiting flowers in search of nectar. They do not live as long as the wingless females.