Lina Wertmuller's "The Seduction of Mimi," a frazzled, wayward farce about the wounded sexual vanity of a Sicilian working-class bigamist, never seemed a promising pretext for a Richard Pryor comedy.

One's initial skepticism is largely vindicated by the Americanization of her film, "Which Way Is Up?" in which Pryor assumes the role of the pathetic bigamist originally played by Giancarlo Giannini and throws in two more roles, which permit him sporadically amusing lelbow, room, as a foxy grandpa and a lecherous, hypocritical preacher.

The protagonist, Leroy Jones, is a mild-mannered California farm laborer frustrated at home by the timidity of his wife, Annie Mae (Margaret Avery), and the bossiness of his obstreperous, sexually robust old dad, Rufus. Forced out of town when he inadvertently aligns himself with labor organizers, Leroy migrates to Los Angeles, where he lands a job as a housepainter and succeeds in wooing a beauty named Vanetta (Lonette McKee), who becomes his common-law spouse and the mother of his firstborn child.

Following doggedly in the footsteps of the Wertmuller plot, screenwriters Carl Gottlieb and Cecil Brown depict a now prosperous Leroy returning to his home-town, where he has accepted a job as manager at a cannery and intends to ead a double life, maintaining households on opposite sides of town. Curiously, the complications that might ensued from this deception are never exploited. The issue becomes Leroy's rageat his neglected wife for becoming pregnant by another man and his efforts to avenge himself on this man who has couckholded him, the Rev. Lenox Thomas.

Wertmuller's plot seemed to take an ineffective detour even if one gave her the benefit of the doubt about the psychology of her Sicilian sap, who felt insulted by a turn of events that could have liberated him. Credible motivation becomes harder to find in this supposedly American context, where it would make more sense if a scared, sneaky rabbit like Leroy tried to spread himself thin and ended up disappointing both attractive women at his disposal. Rambling and hysterical to begin with, the material now seems culturally unassimilated as well.

Pryor may have had a different European actor, Alec Guiness, and a different European comedy, "The Captian's Paradise," in which Guiness starred as a complacent bigamist, lurking somewhere in the back of his mind. After "The Last Remake of Beau Geste" was released, Marty Feldman confessed that what he originally intended, before getting the titles confused, was spoof of "Four Feathers." It's plausible, since there would have been a leading roled for him in a spoof of "Four Feathers." In a similar respect, a reworking of a Guiness comedy like "The Captian's Paradise" might be more congenial for Pryor than a script a mixed-up as "The Seduction of Mimi."

Obvious as it is, the incestuous nature of Pryor's multiple roles hasn't becomes a pretext for inspired high or low comedy. Pryor is at his funniest as the curt, white-breaded old Rufus, a Freudian rebuke to twerpy Leroy. When Pryor also appears as his own cuckold, you can't help wondering why the script wasn't tailored to have him putting the squeeze on himself from beginning to end.

The basis for Leroy's sexual jealousy seems even shakier when one comtemplates the image of Lonette McKee, perhaps the most gorgeous new face on the American screen. Filmakers interested in a viable idea for an original musical might consider a story built around the trials and tribultions of Julie, the mulatto singer iini "Show Boat," with Lonette McKee, who made an exciting debut as a self-destructive Harlem songstress in the title role of "Sparkle."

Having won this statuesque, rapturously pretty creature, Pryor's Leroy looks inexplicably crazy getting upset about the infidelity of his first wife.There's a scene where she says, "You gotta make me a promise: You won't make love to any other women." A voice from the audience rang out, "Promise, brother, promise!" and one can only say Amen.

Michael Schultz, who also directed "Cooley High," "Car Wash" and "Greased Lightning," hasn't acquired much in the way of comic finesse, but he jas energy, which should suffice for a comedy geared for boisterously obvious sex jokes. you can't miss the funny stuff, although your appetite for it may not be as ravenous as the filmmakers assume.