When Congress reconvened this week, those prowling the Capitol's halls, like kids on their first day back to school, were dressed up for the occasion. The favorite garb for women on the Hill was -- no surprise -- the man-tailored suit.

While in other cities professional women have gained enough confidence to relax the strict "success" uniform, substituting wrap skirts for the straight cut or pleated variety, and sweaters for the jackets, in Washington the standard formula still wins out.

"I feel being a woman on the Hill, in a position held mostly by men, I have to wear a suit," said Nina Martinez, legislative aide to Rep. Joseph R. Skeen (R-N.M.), who was wearing a menswear glen-plaid suit and jewel-neck blouse, and carrying a Gucci satchel. "One can look feminine and professional in a suit."

Nancy Goodman, assistant to lobbyist Morris J. Amitay, likes to wear a dark, floppy bow tie with her glen-plaid suit. "It is a more professional image," said Goodman, who equates a suit not strictly man-tailored with a less professional look. "When I am not in a suit people look at me differently."

Word had gotten to Margaret Wick, a nun from South Dakota, that proper suits were the thing to wear when visiting lawmakers on the Hill. And so when she arrived for her first appointment Monday she was wearing a matching blazer and skirt, striped shirt and soft bow tie. "I know it makes me look like a professional person to wear this," she said as she approached the Dirksen Office Building to call on senators from South Dakota and Iowa.

"The congressman I work for might have a mayor or other constituents in the office and ask me to sit in on a meeting," said Bambi McKibbon-Turner, a grants specialist for Rep. Donald Pease (D-Ohio). "That's why I always wear a suit." Her navy pin-stripe suit had a short jacket and slim skirt. "Dark colors are more professional looking," she said.

Lobbyist Joan Dawson wears a suit more often than not, but usually opts for a less man-tailored style. Earlier this week she was wearing a fuchsia short-jacket suit with a lace-trimmed blouse. "A suit has the look of authority, but I try to avoid being a carbon copy of a man," she said.

Deanna Marlow, legislative assistant to Sen. Mark Andrews (R-N.D.), who was wearing a khaki suit and soft bow tie, wears suits most of the time for the same reason most men wear suits, she said. "It's easier to buy them and it means that I don't have to keep up with fashion." Added Marlow, "In the long run it is less expensive because it costs less and doesn't go out of fashion."

Even through the 90-degree-plus temperatures, many Hill staffers stuck by their suits, their ties and their attache' cases, but wore cotton summer espadrilles or sandals.

Not Marlow, who was perfectly suited from head to toe. "But to tell you the truth, I'd rather be wearing a Lacoste [polo shirt] and blue jeans."