Pilobolus plays the Durham Performing Arts Center for the first time this season as it returns, as always, to the American Dance Festival for a four-show run. The big stage in no way diminishes the plastic-fantastic impact of the evergreen troupe, which brings two new works this year.

The more exciting of these, 2b, was made by Israeli choreographers Inbal Pinto and Avshalom Pollak in collaboration with the four dancers who perform it here. Pinto and Pollak have worked with the company before, on Rushes, which premiered at ADF 2007 and which was danced later in this program — a benefit to both works, as they help to illumine each other. (Pinto’s company also performed at Carolina last November.) 2b is a fascinating conundrum, a place — underwater? — inhabited by mysterious characters and a fish? — shark? — iguana? — who go in and out of a tiny red door, hang from a trapeze that appears to be suspended on a light beam, pop black balloons, and engage in other logic-defying but meaningful activities, to music by Tom Waits, J.S. Bach, and Elvis Presley. There are storms, and mournful boat horns, and water sounds, and a stream of images that would reward repeated viewings. In this way it is very like Rushes, which reveals itself a little more when the viewer is not so slack-jawed at the surreality of it all. I particularly enjoyed the projected dreams (looking like Pilobolus creatures) of the suitcase-carrying magic-man this time around, and the way he morphed into a tinker, hung about with chairs. Later, when the chairs had been righted and returned to orderly formation, he stands atop one, a woman clinging to his chest. Slowly the suitcase is returned to his waiting hand; the woman’s hand rises to switch off the suspended light bulb above. As the stage darkens, the impulse to cry out may fill your throat — don’t leave us!

The other new piece, Redline, didn’t quite have that magic Pilobolean compound of seriousness and play. It did have an unsettling confrontational, almost militaristic, tone — although at times the six dancers seemed more like competitive mountain climbers. There were some striking visual effects, but the sense of threat made one uneasy with the flipping and vaulting and crashing.

Two older dances round out the program. The bright slapstick classic from 1971, Walklyndon, rarely performed in the adult programs here, elicited joyous audience response and excited shrieking from the younger patrons. And why not? It’s a hoot, with its bright yellow costumes and silly pratfalls. The elegant Ocellus, from 1972, reminds us why we all fell in love with Pilobolus in the first place: beautiful bodies flowing through shapes in ever-shifting sculptural forms. The four barely-clothed men angle and arc like Antoine Bourdelle’s bold bronze archer heroes, life-sized but fully dominant of their landscapes.

Ocellus is another dance that had slipped from the repertory and whose revival has been funded by the NEA as part of its American Masterpieces Dance Initiative, as was Sue’s Leg, the Twyla Tharp work danced by the Aspen Santa Fe Ballet earlier in the ADF season. Increasingly, we are seeing the institutions of a no-longer-new art form take up the burden of its history. That, along with the necessity of healthy ticket sale income for ADF, leaves less room in the programming for the young and the challenging. A company like Pilobolus makes new work, some of it excellent — but it is not making it in radical or subversive new ways. In its 76th year, the ADF carries a lot of responsibility for maintaining the history and traditions of modern dance. It is just learning to handle the past’s backward drag, learning to calculate the forward thrust needed to sweep history along behind itself like a great peacock tail (or an H. Art Chaos costume) as it pecks and shrieks into the bizarre new modernity of this century — toward the work as yet unimagined that will turn out to be as worthy of saving as Ocellus.

Pilobolus continues at ADF through July 11. See our calendar for details of the evening and matinee performances.