UPDATED: After some more digging, I think they are just Pseudococcidae, which is what Lucy Dinsmore thought they were initially. So they are not braconids, sadly, and thus will not be any help for controlling spotted lanternfllies. Sorry to get your hopes up.
If you see an egg mass, nymph, or adult that is parasitized by wasps or infected by fungi, report it immediately — ideally to both iNaturalist and to your local extension agent — AND collect it in case somebody wants it. And tell me about it, too, please.
I think this is Eris flava, but happy to be corrected. Like every jumping spider I’ve photographed it held onto its prey even while I chased it around the leaf to get the shot. I think I’ve seen a jumping spider discard its prey only once, and perhaps that instance was a spider that had pretty much finished the meal. If you know of any papers on the topic of prey retention under threat, I’d be interested.
If you’re curious, the fly probably isn’t dead yet. Just paralyzed and being digested from within with enzymes injected by the spider. I’d wager the process is exquisitely unpleasant for the fly. I’m assuming the spider moves to different parts of the fly to access different pockets of muscle and such but I couldn’t confirm that in the literature.
If you’re interested in identifying something that’s similar, there’s a useful paper on differences of E. flava and E. militaris by Madison 1986 (pdf), but illustrations of the head are only of males. Photographs and other information are at BugGuide.
Pyractomena borealis (Lampyridae) exploring the surface of trees on a warm winter day in February. At first I thought it might be foraging — they are highly predaceous, and hunt slugs and earthworms (in packs!) by first injecting them with paralytics. But it turns out they are just looking for a place to pupate.
Here is a close-up of the fully retractable head. Those mandibles are hollow.
Here’s a photograph showing a retracted head.
Adults of this species will emerge from pupae sometime in early Spring to be the first fireflies in the area.
The larvae are bioluminescent, too, by the way. The hypothesis about why the larvae glow is that it evolved first as an aposematic trait in larvae, warning mice and toads of the presence of lucibufagins, steroidal toxins in the hemolymph. It’s thought that the adult habit of using flashes is secondarily evolved, millions of years after the larvae evolved the ability to glow. The ability of larvae to glow even predates the origin of the Lampyridae, I gather. For more enlightening details, see Branham and Wezel (2003), Stanger-Hall et al. (2007), and Martin et al. 2017.