Britney Spears is back to attacking her little sister, Jamie Lynn Spears — out here calling her a “bitch” … this while going on and on about things that just don’t make sense.

The pop star posted a few since-deleted videos to her Instagram Story Tuesday, which features in the passenger seat of a car … with three other people with her, including what appears to be her assistant — at least that’s how Brit describes her anyway.

The footage is strange … the group is going up the side of some mountain, following a Jeep that seems to be leading them somewhere remote. Britney and the gang say they’re going horseback riding — which, if accurate, jibes with other posts of hers from earlier in the week.

Everything seems relatively innocent at first, but right off the bat … it’s clear BS is using this as a way to take a shot at JLS — as well as her stint on ‘I’m a Celebrity … Get Me Out of Here!’

Take a listen … Britney says they’re heading into the “jungle” … where she says Jamie was getting “bathed” on TV. She’s referring to Jamie Lynn’s time on the show … and took the opportunity to call Jamie Lynn a “little s***” and a “little bitch” repeatedly in the diatribe.

Britney’s also going in and out of accents here — apparently trying to match her female cohort’s British accent. She talks about getting a vagina rash by peeing in the bushes.

Britney then goes on joke about running out of wine, and then calling her manager to fly her and her friends somewhere on a helicopter … but only with BS’s favorite pilot, who she has a crush on. Yeah … like we said, it’s all over the place — and isn’t very coherent at all.

What’s interesting of course is that Brit is carrying on with her life like nothing’s amiss — even though we’ve been assured things are falling apart at the seams for her, and it’s dire.

We know she’s blowing through cash at a rapid pace … and that she’s in danger of running the well dry. While she’s clearly kidding in this clip, her chopper reference is … well, telling.

In any case … it seems like whatever truce Britney and Jamie Lynn struck in the past is torn up now — sounds like big sis has it out for her younger sibling … and letting it be known.