"An American Repertory" is the title of three relatively unfamiliar plays Paradise Island Express has linked together for three separate evenings at the Washington Project for the Arts. Performances at 1227 G St. NW are Wednesday through Sunday evenings through Nov. 19.

The package is not so rich as it sounds, for these are three short plays for two players. To their credit, Deidre Lavrakas and Jack Halstead, who perform all six roles, have the assurance of veteran stars working with classical roles.

The plays, however, are something else. The best of them is the newest, Paul Lavrakas's "Paraguay," which resumes tonight. The male's identity is the theme of this duel between a woman and a familiar, a premise not unlike Molnar's "The Guardsman." While the situation is overdrawn, the Lavrakas dialogue is at least superior to that of the other two plays.

Alternating in this repertoire are Tom Eyen's "The White Whore and the Bit Player" of 1964 and Michael McClure's "The Beard," which came out the next year.

"The Bit Player" of Eyen's play is a male in drag as a nun, and his exchanges with "The White Whore" consist of the juvenile smut which Off-Broadway was admiring a decade ago. It is a tasteless slice of tripe and uses the usual cheap jabs at religion indulged in by those who assume they are the first thinking members of the human family.

"The Beard" concerns an imagined sexual encounter in afterlife between Jean Harlow and Billy the Kid. Even more than the Eyen playlet, this is one result of bringing up the young on old movies and movie trivia.