Phallapodemic sclerite

Within the Chloropidae family-group there occur different degrees of fusion between the phallapodemic sclerite, hypandrium and pregonites:
In the Carnidae, the phallapodemic sclerite is either free (Hemeromyia sp., according to Griffiths 1972), fused laterally with the hypandrium (Meoneura sp., according to Griffiths 1972; Hemeromyia sp., according to Wheeler 1994), fused with the hypandrium and the bases of the pregonites (Hemeromyia sp. 1), or absent (Neomeoneurites, according to Wheeler 1994). The Carnidae are therefore not suitable for an outgroup comparison of this character so long as the ground pattern of the genitalia of this family has not been established.
In the Acartophthalmidae, a fusion of the phallapodemic sclerite with the hypandrium and the bases of the pregonites occurs, without a reduction of the median part of the hypandrium. According to Andersson (1977), the phallapodemic sclerite in the Acartophthalmidae is not fused with the hypandrium, but only linked via membranes anteriorly to the hypandrium and laterally to the discrete pregonites. Based on my own studies, I disagree with Andersson’s conclusion, but agree with Griffiths’ (1972) opinion that there actually is a fusion.
In the Chloropidae there is no fusion between the phallapodemic sclerite, pregonites and hypandrium.
Within the Milichiidae there is no fusion between the phallapodemic sclerite, pregonites and hypandrium in Neophyllomyza, Paramyia, and Phyllomyza. In Aldrichiomyza, Stomosis, and Xenophyllomyza, the phallapodemic sclerite is fused with the median part of the hypandrium. In the Milichiinae and Madizinae, the phallapodemic sclerite is fused with the bases of the pregonites and the free anterior ends of the hypandrial arms. The median part of the hypandrial arc is reduced.
Since there are different states of fusion between the phallapodemic sclerite, hypandrium, and pregonites in each family, the stem-species pattern of the Chloropidae family-group is difficult to assess. Either the phallapodemic sclerite is free in the stem-species pattern and fusions occurred several times convergently, or the fusion in the Acartophthalmidae and part of the Carnidae represents the stem-species pattern and was changed or reversed several times convergently.
In my opinion there is (either plesiomorphically or apomorphically) no fusion between the phallapodemic sclerite, pregonites and hypandrium in the stem-species pattern of the Milichiidae+Chloropidae. As a consequence it must be assumed that this condition represents the character state in the stem-species pattern of the Milichiidae. In this case, the fusion between the phallapodemic sclerite and the middle of the hypandrium is an apomorphy for stem-species F (Stomosis, Xenophyllomyza+Aldrichiomyza). The fusion between the phallapodemic sclerite, pregonites, and hypandrial arms, combined with a reduction of the median part of the hypandrium, is an apomorphy for the Milichiinae+Madizinae (stem-species G).
(ex Brake 2000)