Life history and description of adults and immature stages of Procecidochares blanci, n. sp (Diptera : Tephritidae) on Isocoma acradenia (E. Greene) E. Greene (Asteraceae) in southern California

Procecidochares blanci, n. sp. is described as eggs, first-, second- and th ird-instar larvae, puparia, and adults. Adults are readily distinguished fr om all North American congeners, for which a preliminary key is provided, b y the absence of dark pigmentation on the anterior abdominal segments or po rtions thereof. The first instar has a dorsally grooved, anterior mouthhook ; the mouthhook of the second instar has four teeth, the most reported to d ate among nonfrugivorous tephritids. The anterior spiracles of the second a nd third instars are flattered and recessed. The oral ridges increase from none in the first instar, to one in the second instar, to two in the third instar. Procecidochares blanci is a true monophage on Isocoma acradenia (E. Greene) E. Greene, on which it produces two annual generations, one floriv orous, which alternates with a longer generation that spends most of the wi nter, spring, and summer as a first instar inside a slowly developing, axil lary bud/branch gall. The florivorous generation feeds within chambers exca vated from adjacent, hypertrophied ovules. Mesopolobus sp. (Hymenoptera: Pt eromalidae), Eurytoma veronia Bugbee (Hymenoptera: Eurytomidae), and E. sp. nr. tumoris are reported as primary, solitary, larval-pupal endoparasitoid s of P. blanci.