Developmental biology and larval morphology of Chromatomyia fuscula (ZETTERSTEDT) (dipt., Agromyzidae)

The egg stadium of Chromatomyia fuscula (ZETTERSTEDT, 1838) (collected in S outhern Norway) takes 4.5 days to hatch in June. The first instar larva (4. 5-6.5 days) is metapneustic and the 2nd instar (6.5-9.5 days) is amphipneus tic. The third instar has a pair of Fan-like anterior spiracles with 18-20 digits each and a pair of posterior spiracles with 5-8 pores, each arranged in 2 rows. Pupariation takes place between the 12.5th and 15th day. During sclerotization and melanization firstly blackish "V" shape stripes develop on the ventral puparial side which enlarge later and merge to a wide black spot, but the dorsal side remains usually yellowish and transparent. Pupal moult occurs within the puparial shell 2-3 days after the white pre-pupari al phase, After. 4 days, the imaginal transformation lakes place. After a f urther 5 days, the pharate phase adult with white eyes turns to the orange eye phase. The following day, the red eye phase occurs. The next day bristl e formation takes place: wings and bristles are greyish, later turn to blac k. During the following 1-2 days, the procuticle phase adult emerges. Adult s are not attracted to either young; or old spring barley plants, but look for a sheltered, humid place. A very long imaginal aestivation and hibernat ion period starts, which is a very uncommon overwintering strategy among ag romyzid flies.