Blacher and Mennin Coming.

Boris Blacher, the director of Berlin's famed Hochschule for Musik, and Peter Mennin, president of the Juilliard School of Music and of the Naumberg Foundation, have accepted invitations to be composers-in-residence at this summer's Congregation of the Arts.

Witold Lutoslawski of Poland had previously accepted Director of Music Mario di Bonaventura's invitation to participate.

The music program of the Congregation of the Arts will open on June 27 with a program featuring the works of Mr. Mennin, the first of the visiting composers. Among the works to be played are his cello and piano concertos.

Mr. Mennin, whose compositions have been performed by all the major orchestras in the United States, Europe, South America, and the Orient, joined the Composition Faculty of the Juilliard School in 1947 and became its president in 1962. His compositions include seven symphonies, concertos for piano and orchestra and cello and orchestra, works for chamber and string orchestras, and for the various choral combinations and for band.

Mr. Blacher, who will be at the Hopkins Center from August 8 to 20, will be visiting this country for the first time in eleven years. His wife, Gerty Herzog, a distinguished pianist in her own right, will make her American debut at the Hopkins Center in the United States premiere of two Blacher piano concertos.

The music program this summer will again feature an examination in depth of the works of the three resident composers. Prof, di Bonaventura will conduct the Dartmouth Symphony Orchestra in a series of concerts, and each of the composers will present a series of four lectures on his work.