R.E.O. Speedwagon and Styx [ tickets ], both of whom emerged from Chicago battle-of-the-bands competitions in the early 1970s to become two of the top-selling rock acts of the late 1970s and early '80s, will team for a two-month amphitheater tour that gets underway in early May.

Though R.E.O. Speedwagon and Styx have sold a combined total of more than 65 million albums over the years, the bands' touring lineups will differ from those of their heydays.

Styx will feature guitarist/vocalist Tommy Shaw and guitarist/vocalist James ''JY'' Young, both original band members. Joining them will be bassist Glen Burtnick (who briefly replaced Shaw in Styx's 1983 lineup), Lawrence Gowan on keyboards and vocals, and drummer Todd Sucherman. Original bassist Chuck Panozzo will appear on select dates.

Missing from the lineup will be Dennis DeYoung. Of late, DeYoung has been playing solo concerts backed by a full symphony. DeYoung appeared on the latest Styx album, 1999's ''Brave New World.''

R.E.O.'s touring lineup will include singer-songwriter Kevin Cronin, keyboardist and founding member Neal Doughty, and original bass guitarist Bruce Hall. Dave Amato, a former lead guitarist for Ted Nugent, joined the band in 1990, as did drummer Bryan Hitt of Wang Chung.

Survivor [ tickets ], of "Eye of the Tiger" fame, will appear on select dates. Group members Frankie Sullivan and Jimi Jamison had been touring with separate bands in recent years, each using the Survivor name. Pollstar reports that the two have put an end to various lawsuits over the use of the name, and are now touring together as Survivor.