Small stocks generally lagged behind the larger market for most of the day Tuesday, thanks in part to a series of poor earnings reports.

APAC Customer Services ( APAC) took a nosedive after losing a nickel a share (excluding items) in the first quarter against Wall Street's expectations for a 2-cent loss, according to Thomson Financial. The Deerfield, Ill., company's sales, at $52.4 million, also narrowly missed estimates. Shares gave up 27.5% to $3.11.

Cutera ( CUTR), maker of laser-based systems for aesthetic treatments, came in a penny below estimates and issued soft guidance for the second quarter and for all of 2007, prompting Merriman Curhan Ford to downgrade the stock to neutral from buy. The California-based company plummeted 21.1% to $23.06.

Oklahoma-based Bronco Drilling Co. ( BRNC) plunged 11.7% to $16.79 after first-quarter earnings retreated 4 cents from last year to 44 cents a share -- 9 cents short of the average Street target -- and UFP Technologies ( UFPT) reported wilting earnings and revenue. Shares of the Georgetown, Mass., packaging maker were off 11.4% to $5.67.

On the more sparsely populated upside Tuesday was United-Guardian ( UG), maker of cosmetic ingredients and other products. Earnings rose sharply to $1.2 million, or 23 cents a share, compared with 13 cents a share last year. Shares of the Hauppauge, N.Y., company soared $3.40, or 36%, to $12.85.

Also rising on positive first-quarter earnings were Houston-based engineering firm ENGlobal ( ENG), surging 25.7% to $8.17; Astronics ( ATRO), an East Aurora, N.Y., maker of lighting and power-generation systems, leaping 21.3% to $25.16; and Internet-software firm Lionbridge Technologies ( LIOX), recently up 15.4% to $6.01.

Elsewhere, Tri-S Security ( TRIS), of Alpharetta, Ga., vaulted 30.3% to $3.54 on word it struck a new $30 million, five-year contract for security-guard services with the Department of Homeland Security.

The Russell 2000 and S&P SmallCap 600 indices were recently losing 0.3% apiece.