But it is quite correct for a gentleman to go into a stranger's box to speak to a lady who is a friend of his, just as he would go to see her if she were staying in a stranger's house. But he should not go into the box of one he does not know, to speak to a lady with whom he has only a slight acquaintance, since visits are not paid quite so casually to ladies who are themselves visitors. Upon a gentleman's entering a box it is obligatory for whoever is sitting behind the lady to whom the arriving gentleman's visit is addressed, to relinquish his chair. Another point of etiquette is that a gentleman must never leave the ladies of his own box alone. Occasionally it happens that the gentlemen in Mrs. Gilding's box, for instance, have all relinquished their places to visitors and have themselves gone to Mrs. Worldly's or Mrs. Jones' or Mrs. Town's boxes. Mrs. Gilding's guests must, from the vantage point of the Worldly, Jones or Town boxes, keep a watchful eye on their hostess and instantly return to her support when they see her visitors about to leave, even though the ladies whom they are momentarily visiting be left to themselves. It is of course the duty of the other gentlemen who came to the opera with Mrs. Worldly, Mrs. Jones or Mrs. Town to hurry to them. A gentleman must never stay in any box that he does not belong in, after the lowering of the lights for the curtain. Nor, in spite of cartoons to the contrary, does good taste permit conversation during the performance or during the overture. Box holders arriving late or leaving before the final curtain do so as quietly as possible and always without speaking. =A "BRILLIANT OPERA NIGHT"= A "brilliant opera night," which one often hears spoken of (meaning merely that all the boxes are occupied, and that the ladies are more elaborately dressed than usual) is generally a night when a leader of fashion such as Mrs. Worldly, Mrs. Gilding, or Mrs. Toplofty, is giving a ball; and most of the holders of the parterre boxes are in ball dresses, with an unusual display of jewels. Or a house will be particularly "brilliant" if a very great singer is appearing in a new rôle, or if a personage be present, as when Marshal Joffre went to the Metropolitan. =AFTER THE PERFORMANCE= One gentleman, at least, must wait in the carriage lobby until all the ladies in his party have driven away. _Never_ under any circumstances may "the last" gentleman leave a lady standing alone on the sidewalk. It is the duty of the hostess to take all unattended ladies home who have not a private conveyance of their own, but the obligation does not extend to married couples or odd men. But if a married lady or widow has ordered her own car to come for her, the odd gentleman waits with her until it appears. It is then considerate for her to offer him a "lift," but it is equally proper for her to thank him for waiting and drive off alone. =AT THE THEATER=