When a house is to be filled with friends of daughters or sons of the house, the young people in the habit of coming to the house, or young men, whether making a first visit or not, do not need any invitation further than one given them verbally by a daughter, or even a son. But a married couple, or a young girl invited for the first time, should have the verbal invitation of daughter or son seconded by a note or at least a telephone message sent by the mother herself. Every one is always asked for a specified time. Even a near relative comes definitely for a week, or a month, or whatever period is selected. This is because other plans have to be made by the owners of the house, such as inviting another group of guests, or preparing to go away themselves. =WHO ARE ASKED ON HOUSE PARTIES= Excepting when strangers bring influential letters of introduction, or when a relative or very intimate friend recently married is invited with her new husband or his bride, only very large and general house parties include any one who is not an intimate friend. At least seventy per cent of American house parties are young people, either single or not long married, and, in any event, all those asked to any one party--unless the hostess is a failure (or a genius)--belong to the same social group. Perhaps a more broad-minded attitude prevails among young people in other parts of the country, but wilfully narrow-minded Miss Young New York is very chary of accepting an invitation until she finds out who among her particular friends are also invited. If Mrs. Stranger asks her for a week-end, no matter how much she may like Mrs. Stranger personally, she at once telephones two or three of her own group. If some of them are going, she "accepts with pleasure," but if not, the chances are she "regrets." If, on the other hand, she is asked by the Gildings, she accepts at once. Not merely because Golden Hall is the ultimate in luxury, but because Mrs. Gilding has a gift for entertaining, including her selection of people, amounting to genius. On the other hand, Miss Young New York would accept with equal alacrity the invitation of the Jack Littlehouses, where there is no luxury at all. Here in fact, a guest is quite as likely as not to be pressed into service as auxiliary nurse, gardener or chauffeur. But the personality of the host and hostess is such that there is scarcely a day in the week when the motors of the most popular of the younger set are not parked at the Littlehouse door. =PEOPLE WE LOVE TO STAY WITH=