Ushering in the spring joke season, one of the most successful hoaxes in recent years was perpetrated at noon yesterday when 1500 birth-control conscious undergraduates were lured to the New Lecture Hall by an unknown pied piper.

Apparently this Mr. X went around to every mailbox in the college at about 2 o'clock yesterday morning and dropped a little card, reputedly from the Department of Hygiene, announcing a lecture on "The Scientific Aspects of Birth Control." Dr. Arnold N. Childes, a mythical medico, was scheduled to give the lecture.

Students who began to gather around the doors of the New Lecture Hall a few minutes before noon, found to their surprise that the doors were locked. Five minutes later a crowd estimated at between 1500 and 2000 persons was milling around the two entrances to the auditorium. When it became evident that the whole affair was a gigantic hoax, a muttering arose from the assemblage which culminated in a few "Rhineharts" and epithetical side-lights.

Wary members of the student body spent most of the forenoon telephoning the Hygiene Building for verification of the circular. In each instance the authorities, their patience wearing thin, replied that the whole thing was a "phony."

That the doors to the New Lecture Hall were locked and bolted when the first of the group arrived, has been laid to the cunning of Col. Charles R. Apted, who yesterday afternoon vigorously denied that the doors were locked with malice aforethought. According to his statement the doors are always locked by the janitor when no class is scheduled to be held in the hall. Furthermore, he was inclined to pooh-pooh the matter as being a trivial incident.

Not so trivial, however, is the Colonel's statement that in distributing their cards the malefactors violated a Federal Postal Regulation, which prohibits the placing of such material in University mailboxes without its first having been postmarked and sent through the regular mail channels.

Dr. Arlie V. Bock, head of the Department, said yesterday that he was "disgusted" by the proceedings and that if the perpetrators were apprehended he would recommend their dismissal unless there were a number of extenuating circumstances in the case.

Sole clue to the affair was a drunk who yesterday afternoon entertained residents of Leverett and Lowell Houses whose windows face on Plympton Street with a lengthy, dissertation on "Sex and The Monetary Instinct."