LIFE-HISTORY AND DESCRIPTIONS OF IMMATURE STAGES OF TRUPANEA-ACTINOBOLA (LOEW) (DIPTERA, TEPHRITIDAE) ON ACAMPTOPAPPUS-SPHAEROCEPHALUS (HARVEY AND GRAY) GRAY (ASTERACEAE) IN SOUTHERN CALIFORNIA

Trupanea actinobola (Loew) is an oligophagous, bivoltine fruit fly (Di ptera: Tephritidae) infesting flower heads of Acamptopappus, Amphipapp us, Bailyea, Chlorocantha, Gutierrezia, Psilostrophe, and Trichoptiliu m spp. (Asteraceae) in southern California, and other plant genera thr oughout much of the United States. Two different-sized morphs are repo rted from California; the smaller one and subject of the present paper , is associated with Acamptopappus, Amphipappus, and Gutierrezia spp. in the subtribe Solidagininae of the tribe Astereae; the larger is ass ociated with Bailyea, Psilostrophe, and Trichoptilium spp. in the subt ribe Gaillardiinae of the tribe Helenieae. An uncommon, apparently int ermediate-sized, presumably different biotype reared from flower heads of C. spinosus, a plant introduced into southern California from Mexi co and Central America, may belong to a different, eastern United Stat es' form of T. actinobola with different host affinities in the tribe Astereae. Trupanea actinobola sensu late has now been reported from fi ve tribes, eight subtribes, 14 genera, and 27 species of Asteraceae. T he egg, first-third instars, and puparium obtained from Acamptopappus sphaerocephalus (Harvey and Gray) Gray are described and figured. The third instar larva bears a pair of elongated integumental petals dorso mediad of the mouth hooks, which have not been seen in the eight other California congeners described to date. The metathoracic lateral spir acular complex consists of a verruciform sensillum, and the abdominal lateral spiracular complex consists of a placoid-type sensillum; thus the lateral spiracular complex is the only morphological. feature obse rved to differ among third instars of each of nine species of Trupanea studied to date. The life cycle of T. actinobola in southern Californ ia is of the aggregative type. Eggs are laid in closed, preblossom flo wer heads and inserted through the overlapping phyllaries. First insta rs feed on the ovules and florets, second instars on ovules, and third instars principally on the soft achenes. The receptacles of infested flower heads are not pitted by larval feeding. Four species of chalcid oid Hymenoptera were reared from individual puparia and mature flower heads bearing puparia of T. actinobola as solitary, primary, larval-pu pal endoparasitoids: Eurytoma veronia Bugbee (Eurytomidae), Halticopte ra sp. (Pteromalidae), Mesopolobus sp. (Pteromalidae), Pteromalus sp. (Pteromalidae).