Speaker of the House Jim Amann and House Majority Leader Chris Donovan will host a news conference Tuesday afternoon to announce that Democrats have added another member to their caucus.Sources say Republican Rep. Diana Urban, R-North Stonington, will be making the switch from Republican to Democrat. She will be discussing her decision to switch at the news conference this afternoon. House Democrats picked up seven seats on Election Day to increase their membership to 106. The switch will increase the margin from 107 Democrats to 44 Republicans.Learn more about Urban, who considered a run for the U.S. Senate late this summer, by clicking here.