Life history and description of immature stages of Neaspilota wilsoni Blanc and Foote (Diptera : Tephritidae) on Hazardia squarrosa (Hooker and Arnott) E. Greene (Asteraceae) in southern California

Neaspilota wilsoni Blanc and Foote is a univoltine, monophagous fruit fly ( Diptera: Tephritidae) developing in the flower heads of Hazardia squarrosa (Hooker and Arnott) E. Greene in southern California. The egg, first-, seco nd-, and third-instar larvae, and puparium are described and figured. The e gg pedicel is conical and completely circumscribed by many, shallow aeopyle s of various sizes. The mouth hooks of all three instars are bidentate. The intersegmental areas of the first instar bear minute acanthae of a heretof ore unreported form, i.e., cylindrical and apically bearing one to five pro ngs. Also newly reported, the caudal segment of the first instar bears stel ex sensilla, each basally ringed with one to three, upright, pointed acanth ae. The integumental petal is laterally fused with the stomal sense organ i n the first instar, but separate in the second instar. The larvae feed main ly on the ovules and soft achenes as first and second instars; however, as third instars, they usually extend their feeding into the receptacle and ad ditionally feed on sap that collects in the shallow scars. The nonfeeding p repuparium overwinters in a protective cell that occupies much of the excav ated flower head and is formed of floret, pappus, and achene fragments impr egnated with excess sap and liquid feces that harden when dry. A few prepup aria pupariate and emerge as adults in the fall and overwinter, but most pu pariate in late winter to early spring, and emerge as adults that aggregate in summer on preblossom host plants to mate and subsequently oviposit. A s ingle male specimen of Eurytoma veronia Bugbee (Hymenoptera: Eurytomidae) w as reared from a puparium of N. wilsoni as a solitary, larval-pupal endopar asitoid.