LIFE-HISTORY AND DESCRIPTION OF IMMATURE STAGES OF UROPHORA-TIMBERLAKEI BLANC AND FOOTE (DIPTERA, TEPHRITIDAE) ON NATIVE ASTERACEAE IN SOUTHERN CALIFORNIA

Urophora timberlakei Blanc and Foote is a bivoltine, probably trivolti ne, tephritid which develops in the flower heads of Acamptopappus, Amp hipappus, Chrysothamnus, and Haplopappus spp. in southern California. For the first time, the egg, second and third instar larvae, and pupar ium are described, and the larvae and puparium are figured. Distinctiv e morphological features noted for the immature stages include eggs th at are smaller and of a shape different from Palearctic Urophora. The third instars resemble certain described Palearctic Urophora, but they differ from larvae of other Nearctic tephritids in having a bluntly t runcated, dark brown to black caudal segment covered by minute dome-sh aped papillae and bearing several deep pits mediad and ventrad of the posterior spiracular plates. The verruciform sensilla circumscribing t he prothorax and the wedge-shaped acanthae that circumscribe the meso- , metathoracic, and abdominal segments also are distinctive features. The larvae feed mainly on the ovules and soft achenes. Pupariation occ urs in the larval feeding chamber among fragments of achenes. Prematin g and mating behaviors are described for the first time for any Nearct ic Urophora, distinguished only by the males displaying abdominal pleu ral distensions throughout courtship and copulation. Eupelmus sp. (Hym enoptera: Eupelmidae) is reported as a solitary, endoparasitic, larval -pupal or pupal parasitoid.