Bellow's first story collection since '71 - impressive but strainedHim with His Foot in His Mouth and Other Stories, by Saul Bellow. Harper & Row. 294 pp.

Saul Bellow's first collection of short fiction since 1971 opens with its vivid and clamorous title story. In it a musicologist on the lam from creditors and living in British Columbia imagines himself writing an extended letter of apology to a woman he once insulted.

The writer (narrator), Shawmut, rehearses old loves and hates, muses over ''his compulsion to make jokes that humiliate and destroy,'' and finds an objective correlative for his own insecurities in poet Allen Ginsberg's ''psychopathic vision . . . (and) screwball defense of beauty.'' The story becomes a rich rhetorical cry of pain from a familiar Bellow type: the unflappably fluent, energetic egotist.

The style is feisty and funny; Bellow's ''late'' manner - unlike, say, Henry James's - is breezier and more direct than his earlier prose. The speaking voices in the stories gathered here are possessed of an admirable vigor and drive. The trouble is that, particulars aside, the stories all sound the same; I found they grated on my ear and wore down the goodwill I'd brought to the book.

''Zetland: By a Character Witness'' is a memoir of an all-purpose intellectual eccentric who has been identified as Bellow's old comrade Isaac Rosenfeld; the story feels like a fragment from an abandoned longer work. ''Cousins'' sketches the travail of Ijah Brodsky, a lawyer and ''media personality'' unwillingly entangled with a ragtag family that harbors several visionary losers and petty criminals, and to which his own family owes a debt of gratitude: It's a comic rhapsody about the complexities bred by respect for family feeling. In ''A Silver Dish,'' much the best of these three, the tense relationship between a prodigal old man and his responsible, hardworking son leads to the latter's muted realization that ''Pop was no worse than Woody, and Woody was no better than Pop.'' It's a moving story despite a show-offy style that seems to me imperfectly suited to its characters' essential dead seriousness.

Only the long story ''What Kind of Day Did You Have?'' - about an imperious art critic (''one of the intellectual captains of the modern world'') and his subservient mistress - offers both a developed plot and a convincing sense of what its people are really like. Here, Bellow gets beneath his story's colorful surface and gives us something more resonant and truthful than a parade of witty and vibrant summary statements.

The rhetorical energy of these five stories is impressive and distinctive - but it soon reveals, as an old Cole Porter song has it, the faint aroma of performing seals. Besides, isn't there something off-putting about an eminent writer in his 70s who appears to be straining so hard to impress his readers.