Crosby, Stills & Nash [ tickets ] have tacked a fresh leg of summer shows to the end of their forthcoming tour.

The outing kicks off June 3 in St. Louis, MO, and the new dates extend the trek into late September, with the bulk of the newly added shows falling in the month of August. Details are listed below.

In late June and early July the tour moves to Europe for two weeks. Those dates can be found at the outfit's official website.

The outing's launch coincides with the June 2 release on Rhino Records of "Crosby, Stills & Nash Demos," which collects early versions of some of the trio's biggest hits along with a few rarities, including a demo version of 1969's "Marrakesh Express" and the Stephen Stills solo track "My Love is a Gentle Thing" from 1968. The group is currently in the recording studio working on material for a new album with producer Rick Rubin, according to a press release.

CSN first formed in 1968, with each member coming from another influential group: David Crosby from The Byrds, Stephen Stills from Buffalo Springfield and Graham Nash from The Hollies. Their 1969 self-titled debut earned them a Best New Artist Grammy and now sits at No. 259 on Rolling Stone's list of the 500 Greatest Albums of All Time.

CSN's most recent collection of original material is 1994's "After the Storm." The trio joined with Neil Young once again in 1999 for "Looking Forward."