Why are UT students called teasips?

The term tea-sip (also spelled teasip, t-sip, or t sip) was started by students of Texas A&M University (aka. Aggies) in the early 1900's to belittle the well-to-do students of UT.

The University of Texas was traditionally the "rich" school which pumped out doctors, lawyers and the like. A&M was the blue collar school which traditionally taught Agriculture and Mechanics (engineering).