I called the boys out to take a look at her, close up. Definitely a girl, she is far larger than the boy Black Widow Spiders that hang out around here.
I expected the boys to scream or be grossed out, which is their typical reaction toward spiders (maybe they've seen how their mom reacts and are trying to replicate her behavior?) but they were actually very calm and almost respectful when confronted with an actual poisonous spider. Black Widows are very common around here, but this was the largest one I've seen, and the first one the boys have seen (because generally I make Daddy get rid of them before the boys see them).