WASHINGTON - Fed Chairman Alan Greenspan and Treasury Secretary  Robert Rubin are scheduled to appear before the House Banking Committee   tomorrow as the panel begins its examination of the Mexican peso crisis.   
The hearings will focus on the causes of the Dec. 20 devaluation of the  peso and will explore whether the administration had the authority to   pledge $20 billion to help stabilize Mexican markets.   
  
Lawmakers will also consider developing an international mechanism that  would be able better to resolve such international financial crises. 
In addition to Mr. Greenspan and Mr. Rubin, the banking committee will  hear from Secretary of Labor Robert Reich, Secretary of State Warren   Christopher, and Under Secretary of State for Political Affairs Peter   Tarnoff.     
  
The session starts at 2 p.m.
When the committee reconvenes at 10 a.m. on Friday, lawmakers will hear  from a panel of scholars, economists, and members of former   administrations.