Do these sting? I had to feeling the ovipositor would be useless for that.

Having once been pricked by a female of Megarhyssa when transferring it from the net to a killing bottle, I suppose that females of this species would do the same. I don't suppose that there would be any venom injected, though, but I can't say for certain that there wouldn't be. Henry Townes told me that some Neotropical Cryptinae, most of which would have ovipositors shorter than Labena, could inflict a potent sting that would still be sore several days later, unlike the stings of aculeate Hymenoptera, which did not remain sore for nearly that long. The Ichneumonidae that are most likely to sting humans are species of Ophioninae and species of Netelia (Tryphoninae) that are attracted to lights on the exterior of buildings.

for the information. They always seem trapped in there, crawling on the inside of the screen as if looking for a way out. I didn't know, if this upset them, if they'd take it out on available humans with a sting.

No, they would only attempt to escape. The only instance in which they might use the stinging reflex is if they are caught. If you have seen this species on the porch on more than one occasion, is there some reason why that might be so? Hosts include various buprestids and cerambycids. According to Townes, the adults are likely to be encountered around dead bushes or piles of brush.

The house is one that belonged to my friend's grandmother, who passed away a couple years ago. It sits empty except a few times a year when he goes down to check on it. That back porch is in slight disrepair and contains a hot tub that is so far gone that no one will ever use it again. That might count for "dead bushes or piles of brush", maybe? There are large rips in the screen that allow things to easily get in.

I've gone down for a trip with him two years now and the wasps have been in there both times.

Thanks again for the information!

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