There are a lot of spiders that ambush bugs when they get into a web.
House spiders, grass spiders, are typical for this.
I have sothern house spiders about, and they will do that.
Something like this:
Are you thinking of a Trap Door Spider ?
It's big, it makes an entire web around itself, and it waits for prey to get on the web and pulls them inside or something like that, I can't remember what kind of spider it is.
