LIFE-HISTORY AND DESCRIPTION OF IMMATURE STAGES OF TRUPANEA-SIGNATA FOOTE (DIPTERA, TEPHRITIDAE) ON GNAPHALIUM-LUTEO-ALBUM L. IN SOUTHERN CALIFORNIA

Trupanea signata E. is a narrowly oligophagous, multivoltine, gregario us, obligately gallicolous fruit Ay (Diptera: Tephritidae) studied in southern California on Gnaphalium luteo-album L. This host plant is an introduced weedy annual of Old World origin to which this tephritid h as transferred from indigenous, congeneric hosts, an uncommon occurren ce among nonfrugivorous North American Tephritidae. The egg, third-ins tar larva, and puparium are described and figured. The eggs are insert ed into apical and axillary buds. From one to six larvae feed gregario usly within an open cavity in the expanded pith parenchyma of galls on axillary branches and stems during all three instars. The galls are e longate-obclavoidal, sometimes bear axillary branches and flower heads , and are covered by a wooly investiture. Pupariation occurs inside th e gall. The adults emerge and exit the gall through a common channel b y pushing aside a thin, pre-formed, apical, ''gall cap.'' The adults a re long-lived and are the overwintering stage. The life cycle follows the aggregative pattern and at least two generations, one each in spri ng and fall, are produced annually on G. luteo-album. Two species of s olitary, larval-pupal, hymenopterous endoparasitoids are reported: Eur ytoma sp. (Eurytomidae) and Pteromalus sp. (Pteromalidae).