In the stem-species pattern of the Milichiidae and of the Chloropidae family-group, the basoflagellomere is relatively small and rounded in both sexes.
However, in males of Costalima, Microsimus, Neophyllomyza, Paramyia spp., Phyllomyza, and Stomosis sp. the basoflagellomere is larger than in females and often elongate. The enlargement of the basoflagellomere may have evolved once in the stem-species of the Phyllomyzinae, and was secondarily lost in Borneomyia, several Paramyia species, most Stomosis species, and Aldrichiomyza+Xenophyllomyza. On the other hand it is possible that the enlargement evolved in Costalima+(Microsimus+Phyllomyza) and convergently in Neophyllomyza and within Paramyia and Stomosis. In my opinion, the latter hypothesis is more probable because it is more parsimonious.