This Tuesday brings the last big swarm of Democratic primaries. After that, we'll see mostly single state primaries such as Wyoming (Mar 8), Mississippi (Mar 11), Pennsylvania (Apr 22), and stragglers going into May including Indiana, North Carolina, West Virginia, Kentucky, and Oregon. But this coming Tuesday will be the last large grouping of delegates awarded, a total of 444.
Texas has a traditional system using a mix of primary and caucuses for their delegates. First, they have a standard primary which uses a direct ratio of votes to delegates to account for 126 delegates. Early voting started a while back, and ends Tuesday evening.
Then, starting at 7PM Tuesday, the state Democrats will hold caucuses to determine the remaining 67 delegates. So they base 2/3 of the delegates on Primary votes, and 1/3 on Caucus votes.
Plus, there's a rather intricate system involved in awarding the caucus delegates, as depicted in the graphic above. (Click to enlarge it)
Already there's concern about the limited sizes of the caucus places, which may result in smaller turnouts or caucus-goers being turned away. This might work in Clinton's favor, since Obama seems to do better in caucuses. DailyKos is on top of the situation with this story.