Come July, wispy summer dresses and teensy tops — the very items you spent March dreaming about — start to wear a little thin. The midsummer blues have hit. Crisp fall nights? As appealing a dream as, oh, minimizing your leg-hair and bikini-line-maintenance regime. Get a jump start on October today. Alice + Olivia, purveyors of those cute-as-hell pants, have launched a collection of sweaters for fall. The soft, fitted cashmere crewnecks come in the basic colors (light blue and navy, cream and chocolate, pink and white) and have contrasting elbow patches. Think preppy professor with a darn sexy twist. Back to school? Not quite yet. But until the mercury falls again, you can throw them over your shoulders. And pray for some super-cranked A/C. To see the collection, go to aliceandolivia.com. To order, call Saks Fifth Avenue (212-826-8900) or Barneys New York (212-826-8900, ext. 2627).