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Wasp ID
I found this "wasp" or hornet making a nest in an old stump in Connecticut. It was a hot day and there were many of them. What kind is it?
Gary

Hi Gary,
This is not a wasp, but a Mydas Fly. Mydas Flies are often mistaken for wasps. According to our Audubon Guide: “The slender larvae, which reach 1 1/2″ (38mm) when fully grown, live in soil or rotting wood and prey on beetle larvae.” The nest building you thought you observed has two possible explanations in our minds, though the two explanations might be combined. You might have seen a mass emergence of adults from their larval home after metamorphosis or you might have seen a congregation of mating adults laying eggs where the larvae will have a ready food source. You might even have seen the mass emergence of adults and the subsequent mating, with the next generation occupying the ancestral home. Adult flies eat caterpillars, bees, other flies and hemipterans.

Thanks for the info. Dan. I’m not an entomologist, but have a strong interest in nature an photography. My old maple stump (about 1 m. in diameter and dead about 7 years has been a great source of amusement. Every year some new mammal, fungus or group of insects appear!) Keep up your good service to curious people.
Gary

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