Cow ants are commonly referred to as mutillidae, velvet ants or even cow killers. They are actually wasps but resemble ants. They are different from ants because there is a slight narrowness between the thorax and abdomen; they also have straight antennae. Cow ants are normally red, black, white, silvery or golden colored. They received their name because their stings are so painful, they could kill a cow.
Remove water sources. Since cow ants need water, one of the best ways to get rid of them is to remove all excess or standing water sources.
Move their home. Although cow ants do not have any visible nest of their own, they will make their home in bumble bee nest and lay eggs. In addition they will hunt the bumble bee larvae and pupae and kill the bumble bees. Get rid of any bumble bee nests.
Grow grass. Although this is not a quick solution, it is the best long-term solution. Cow ants normally find their prey in pastures and fields with sandy soil. If you over plant the area, you will make it harder for the cow ants to find a food sources.
There are no chemicals available that will kill cow ants because they are relatively uncommon and do little damage.