Bank of Boston added $300 million to its reserve.

New England’s largest bank said it will post losses of between $80 million and $85 million for its second quarter due to the increase to slightly more than $700 million in its reserve to cover loans to Latin American countries. The countries include Argentina, Brazil, Mexico, Chile and Venezuela, said a bank officer, who asked that his name not be used. The company--which ranks as the nation’s 14th-largest bank--is following a trend set by New York-based Citicorp and followed by several other banks in increasing its reserve to cover possibly uncollectable foreign loans.