The principal ceremonies of the Pomo were:
[The xahlū´īgax xaikīlgaiagība][6] ([the "ghost" or "devil" ceremony]).
[The kalīmatōtō xaikīlgaiagība] ([the thunder ceremony]).
INVITATIONS TO CEREMONIES
The captains of the village discussed with other important men the question of holding a ceremony, just as they discussed other matters relating to the general public good. Having agreed upon the date and other details, the head captain usually walked through the village delivering an oration, as was customary upon occasions of importance, in which he announced to the people the decision of their captains. This oration might, however, be delivered as he stood before the door of his own house or before the door of the dance-house.
Invitations were then sent to the people of other villages to attend the ceremony. This was done by means of a special invitation string. Wormwood or willow sticks about two inches in length were tied, each separately, into a short string, the number of sticks being equal, according to some informants, to the number of days intervening before the ceremony was to begin, usually not fewer than two or more than eight. Other informants stated that this number was equal to these intervening days plus the number of days during which the ceremony was to be held. For instance, if a four-day ceremony was to begin four days hence, these being the usual numbers in both instances, eight sticks were tied into the invitation string. According to another informant, if the number of sticks was from two to five, the guests were invited for the first of two or more ceremonies. If six or more sticks were present, they were to come for a later ceremony. This latter, however, seems to be rather improbable. To one end of the string was tied, as an ornament, a small section of forehead-band made of yellow-hammer feathers. This string might be presented as such, but frequently it was tied to the end of a wand about two feet long. Its general name among the Central Pomo was haidel. Before sending, it was called ha'iebū; after it had been sent out, it was termed ha'idakaū.
A messenger took this string or wand to the captain of the village invited and, if it was necessary for him to make a journey of any considerable length, he broke off a stick for each day of his journey. According to most informants, he simply delivered the string to the head captain of the invited village and immediately returned home with the message of acceptance from that village. According to one informant, however, he remained as the guest of the head captain, and himself broke a stick each day from the invitation string and finally conducted the visitors to the ceremony.