To the tune of a rising crescendo of applause, Canada's 65-member folk ensemble, Les Feux Follets, has swung into the exhilarating tempo of the professional theatre which will take them dancing and singing around the world. Born a dozen years ago in Montreal, this folk-dance group has a repertoire which has already dazzled audiences in Canada, the U.S.A. and France and flashed into prominence as the highlight of the Royal variety show performed for the Queen in Charlottetown, P.E.I., last year. Today, with their first professional appearance (at Montreal's splendid Place des Arts) a resounding success, Les Feux Follets are off on a series of tours heading for Australia, New Zealand, South Africa, Europe and North and South America. Included in these plans are participation in the Commonwealth Festival in Great Britain this autumn, the Vancouver Festival in July and performances in nearly 50 cities in Canada and the United States. Les Feux Follets (wills-o-the-wisp) presents a two-hour show that portrays Canada from coast to coast. Titled, A Canadian Mosaic, part one depicts color-drenched scenes, alive with music and dancing, of west-coast and plains Indians in olden days, pioneers on the western trails, gold-rush days in the mountains and modern urban life in industrial Canada. Part two shows old France in the new world with Acadians dancing in wooden shoes, Scottish maritimers singing their songs of the sea, an Eskimo walrus hunt and the feast that follows and life along the historic St. Lawrence. On its world tour, A Canadian Mosaic will show colorful facets of the varied cultures of a widespread land-painted in virile action by the warm tones of living flesh and blood.