The grass in the vicinity of the town of Lourenço Marques is often infested by larval ticks, especially in places frequented by cattle. These ticks are so numerous as to constitute a veritable scourge, since they attack a variety of animals, and man is frequently a victim to their onslaughts. The ticks are especially prevalent in July and August. Their bites may produce merely a local effect, but in some persons general symptoms may follow.