Small Velvet Ant
I found this little ant-like creature on the road while pushing my bike up the hill. She caught my eye because she didn’t look quite right for an ant. For one thing, she was redder than other local ants I’ve seen. For another, thing, her head and abdomen didn’t quite look right to be a local ant (the head was too broad, and the abdomen too conical). And for a third thing, she was pacing along in a fairly deliberate manner, and not scurrying in a random-walk pattern the way that individual ants usually do.
Rather surprisingly (to me), she looks to be a small “Velvet Ant”, specifically Pseudomethoca frigida. This was surprising because I thought that velvet ants were an exclusively southern family, and were never found as far north as Michigan. And yet, here she is! Of course, now that I look them up, I see that this particular species is one of maybe two or three velvet ant species that range fairly far north.
Velvet ants aren’t actually ants. They are a family of wasps where the females are wingless (the males are winged, and look so different that a casual observer would probably not recognize a male/female pair as being in the same family, let alone the same species).
This particular specimen is one of the smaller species, at about 4-5 mm long, and doesn’t have the lush body fuzz that gives the “velvet ant” family their common name. Some of the more-southern species are quite a lot bigger, and so red and fuzzy that they look almost like some sort of plush toy.
I had a lot of trouble getting her to face me, so I’m afraid this is the best picture I could get of her mandibles. She doesn’t have the massive chewing mandibles of a lot of other wasps, probably because she isn’t going to spend her time rounding up and masticating food to give to her offspring.
Instead, she’s going to prowl around until she finds a nest of ground-nesting bees or wasps, slip inside, and lay her eggs on the developing grubs she finds. Unlike a lot of other kleptoparasites, she doesn’t necessarily go after solitary nesters, but will evidently tough it out with whole colonies of bumblebees and yellowjackets and the like. The bigger species of velvet ant are supposed to have such tough hides that the nest defenders have difficulty stinging them, and they just force their way right in even if they are spotted by defenders. But I think this little one is more likely to try to sneak in unnoticed.
Some of the bigger velvet ants have the common name “Cow Killer”, because they have excruciatingly painful stings, and people joke about it being painful enough to kill a cow. I don’t know how painful this one might have been, as she didn’t sting me. Although, she did tend to point her abdomen at my camera quite a bit, so it is possible she intended to sting me.
Although, given her size, I doubt that her sting would have been any worse than what one might get from a “sweat bee” or maybe an individual fire ant.
 Or ants, maybe? All the references I find say that they go after bee and wasp nests, but those references are mostly talking about the bigger velvet ant species, not these little ones. Given her small size, it seems like she could easily raid, say, carpenter ant nests. I’m not seeing any mention of whether small velvet ants actually parasitize ants or not, though.
 Just to be clear, here, they don’t actually kill cows.