You could look at Jeffrey Costello and Robert Tagliapietra's new collection and say that not much has changed. But that's probably just fine with the New York duo's devoted fans. They'd prefer to keep Costello Tagliapietra's skimmy jersey dresses a secret, to ooh and ahh among themselves about a frill of pleats at mid-thigh, a new shirred neckline, or the tiny buttons that render a provocative slit demure.

However, a growing clique of fashion insiders does not a business make. So in addition to elevating the quiet charms of their fall silhouettes—wraps, halter gowns, and sheaths, mostly—with exquisite lace linings, the designers are continuing to add more sportswear separates to their mix. Sturdy moleskin trousers set off a delicate David Hockney-blue sleeveless top very well, but a coat cut from the same fabric that hit at the hips looked boxy; the knee-length version had more swing.

Just when you might have expected them to expand on these ideas, a fox jacket and a raccoon capelet ended Costello Tagliapietra's small collection. If they're committed to growing bigger, the designers will have to spend less time on such fluff, luxe though it may be, and focus more on pieces like the great-looking gathered-shoulder top and slim skirt that were almost obscured by a fur muff.