Abstract The female Indra Swallowtail butterfly lays eggs on a number of species of the genus Lomatium in the Apiaceae family The essential oils of three varieties of Lomatium grayi; L. grayi. var. grayi, L. grayi var. depauperatum and L. grayi. var. (undescribed) have been analyzed. Among the major components, L. grayi var. grayi shows myrcene (8.4%), β-phellandrene/limonene (27.2%), γ-terpinene (10.4%), and senkyunolide (24.4%). L. grayi var. depauperatum shows myrcene (8.1%), p-cymene (4.3%), β-phellandrene/limonene (20.8%), (Z)-β- and (E)-βâocimene (23.6%), γ-terpinene (4.4%), germacrene D (4.6%), senkyunolide (4.7%), and (Z)-ligustilide (6.7%). L. grayi (new varity) shows β-phellandrene/limonene (17.7%), γ-terpinene (16.1%), and senkyunolide (44.0%). These observations contrast signifcantly with the reported composition of L. grayi. Only L. grayi var. depauperatum and L. grayi (new variety) attract the butterfly.