Milichiidae online

In all Cyclorrhapha the male genitalia are rotated through 360 degree (hypopygium circumversum). This rotation occurs near segment 8 and results in a shifting and often a reduction of the sclerites of segments 6 to 8. S6-8 shift to the left and S7 and S8 often fuse to form a single synsternite lying more or less dorsally (Crampton 1941). T6 may be reduced in size or lost, and T7-8 are absent. In all male Diptera the abdomen has only seven spiracles. The 6th and 7th spiracles are either in the sclerotised area of synsternite S7/8, directly next to S7/8 in an only lightly sclerotised area, or in the membrane.
In the stem-species pattern of the Chloropidae family-group, T6 is present but narrow. This assumption is based on the presence of T6 in the stem-species pattern of the Carnidae (Wheeler 1994) and of the Milichiidae. Within the Milichiidae, T6 is present only in Madiza glabra and Stomosis and must have been lost in all other genera. In addition, T6 is lost in the Chloropidae (Andersson 1977) and in the Acartophthalmidae.
In the stem-species pattern of the Chloropidae family-group, as represented in the stem-species pattern of the Carnidae (Neomeoneurites and Hemeromyia) and present in most Schizophora, the pregenital segments are strongly asymmetrical, with S6-8 lying closely joined on the left side. This is the plesiomorphic condition, which is caused by the circumversion of the male genitalia.
An apomorphy of the Acartophthalmidae+(Milichiidae+Chloropidae) (stem-species A) is the formation of a symmetrical, dorsal S7/8. Similar but convergently evolved forms of synsternites can be found, among others, in the Sepsidae. In the Tethinidae and Canacidae, S7/8 is symmetrical as well, but it is fused to the large T6. The presence of a synsternite S7/8 could be an indication that the Tethinidae/Canacidae complex is the sister-group of the Acartophthalmidae+(Milichiidae+Chloropidae). However, further studies are needed to support this hypothesis.
In the Milichiidae and Chloropidae (Andersson 1977), S6 is plesiomorphically fused to the left side of synsternite S7/8. In the Acartophthalmidae, S6 apomorphically forms a ring with S7/8.
Within the Milichiidae, S7/8 is narrow in most species, but can be wider in Stomosis, Madiza, and Neophyllomyza. In some Phyllomyza species slits can be discerned which possibly separate S7 from S8. These slits could thus indicate that this sclerite originated from two fused sclerites. The plesiomorphic condition of S6, in which it is fused to the left side of S7/8, is represented in ?Xenophyllomyza sp. 1 and in Stomosis. In Milichiella sp. 2 and Phyllomyza, S6 convergently joins S7/8 on each side. In all other Milichiidae that I studied, S6 is absent. (ex Brake 2000)