The fig (Ficus) is absolutely dependent upon pollination by minute agaonid wasps for development of fertile seeds. In some species of the wasp genera Agaon, Allotriozoon, Blastophaga, Ceratosolen, Elisabethiella, Liporrhopalum, and Pleistodontes, the females possess concavities ("corbiculae") to carry pollen. The New World Tetrapus and some Old World Blastophaga lack pollen-carrying structures and may carry pollen dusted over the body or in the digestive tract.