Dreyfus Brokerage Services, the discount brokerage arm of Mellon Bank  Corp., plans to offer after-hours trading to retail investors this summer. 
Dreyfus is one of four brokerage firms that have signed up with Eclipse  Trading, a New York firm that has designed the system for investors. The   other three firms signing up for the service are Bernard L. Madoff   Investment Securities, Herzog Heine Geduld, and Discover Brokerage.     
  
Initially, investors will be able to trade electronically between 6 and  9 p.m. on the alternative trading system, said Michael Satow, president and   co-founder of Eclipse Trading.   
"We will expand those hours as the market matures," Mr. Satow said. The  firms and their customers will pay for the service on a per-share basis, he   said, but he declined to disclose the fee schedule.   
  
Mr. Satow and co-founder Eugene Choe are both former Securities and  Exchange Commission enforcement lawyers. Therefore, Mr. Satow said, he is   particularly aware of investor suitability issues in relation to Internet   trading, an area the SEC is currently examining.