Sylvia Plath's first poem about bees, "The Beekeeper's Daughter," predates her own beekeeping activities, and so likely reflects the influence of her father, Otto Plath, whose major entomological study was Bumblebees and Their Ways. Likewise, both the vampire and the Frisco Seal in her poem "Daddy" are almost certainly biographical references to her father's research and publication. The blood-sucking image of the vampire was probably suggested to Plath by her father's study of parasites, "Muscid Larvae of the San Francisco Bay Region Which Sucks Blood of Nesting Birds," a study that documents the endurance, tenacity, and enormous destructiveness of these larvae.
While most of the geographical references in Plath's poetry are to New England or England, "Daddy" refers to San Francisco in the lines "Ghastly statue with one gray toe / Big as a Frisco Seal / And a head in the freakish Atlantic." These lines identify the daddy in the poem as a colossus who stretches across America from the Atlantic to the Pacific--a colossus even larger than the one described in "The Colossus." These seemingly obscure details are in fact references to Plath's father: the "Ghastly statue with one gray toe" is Otto Plath's gangrenous leg, and San Francisco Bay is where he conducted his research on muscid larvae.
WORKS CITED
Plath, Otto. Bumblebees and Their Ways. New York: MacMillan, 1934. Plath, Otto. "Muscid Larvae of the San Francisco Bay Region Which Sucks Blood of Nesting Birds." University of California Publications in Zoology 19 (Feb. 7, 1919), 191-200.