In Greek mythology, Bucolus (Ancient Greek Βουκόλος, "herdsman") is the Athenian father of Sphelus and grandfather of Iasus, the captain of the Athenians whom Aeneas slays in Homer's Iliad. Distinct from other men of the same name — a Hippocoöntid of Sparta, a Thespian son of Heracles, a brother of Ochne in Boeotia, and the nickname of Daphnis.
Adapted from Wikipedia, "Bucolus" · CC BY-SA 4.0
I.Grandfather of Iasus
Homer names Iasus captain of the Athenians as son of Sphelus, son of Bucolus, when Apollo rouses the Trojans and Aeneas smites him among the foremost fighters at the ships (Iliad 15). The poem gives Bucolus no further biography — only this three-generation Athenian stemma.
The atlas id bucolus-athenian locks that Homeric grandfather alone.
II.Homonyms
Wikipedia's Bucolus disambiguation also lists Bucolus son of Hippocoon of Sparta; Bucolus the Thespian son of Heracles and Marse; Bucolus son of Colonus (brother of Echemus, Leon, and Ochne), who with his brothers killed their cousin Eunostus; and Bucolus as a nickname of the herdsman Daphnis. None of those is this Athenian.