The objective of the present study is to describe the karyotype of the fruit fly Tomoplagia rudolphi (Lutz & Lima, 1918). This fly induces the formation of galls on the stems of Vernonia polianthes (Asteraceae). The cytogenetic analysis of cerebral ganglia (larva and pupa) and testis (adults) of T. rudolphi showed a diploid chromosome number of 2n = 10 + xx (female) and 2n = 10 + xy (male). The diploid chromosome number 2n = 12 and the XX/XY sex determination system have been found in most of the species studied. The present investigation constitutes the first cytogenetics study of the genus Tomoplagia Coquilltt, 1910.
Chromosome; Cyclorrhapha; cytogenetic; fruit fly; sex determination