Wet Seal Third-Quarter Net Loss Widens  SAN FRANCISCO (Reuters) - Struggling clothing retailer Wet  Seal Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=WTSLA.O target=/stocks/quickinfo/fullquote"&gt;WTSLA.O&lt;/A&gt; on Wednesday posted a wider quarterly loss  as lackluster demand for its teen-oriented fashions forced the  company to make bigger markdowns.