That would be brown reculses and spiders of the same family. I am not aware of black widow venom causing necrosis, it is a neurotoxin, causing things like para

That would be brown reculses and spiders of the same family. I am not aware of black widow venom causing necrosis, it is a neurotoxin, causing things like paralysis. And indeed, in both cases, serious conditions are rare. Also, many bites are dry bites, where no venom is injected.