What kind of party do Becky’s parents have for her?

Becky's parents have a picnic for her.

Becky teased her mother to appoint the next day for the long-promised and long-delayed picnic, and she consented. The child’s delight was boundless; and Tom’s not more moderate. The invitations were sent out before sunset, and straightway the young folks of the village were thrown into a fever of preparation and pleasurable anticipation.