The Arthur Roger Gallery is presenting an exhibit of paintings and charcoal drawings on paper by Robert Colescott. His combination of master artistry and incisive social criticism has elevated Colescott to the first rank of this country’s social commentators. Flouting taboos Colescott is provocative and unabashedly ribald as he deals head on with race and sex, a subject which excites as much as it bemuses him. Cartoonishly emphatic his Expressionist figurative drawings nevertheless develop networks of internal balance and harmony.