The first cytogenetic analysis of Phlugis Stål, 1861, Phlugis proxima Bruner, 1915, revealed 2n♂ = 27, X0 and 2n♀ = 28, XX. Some tribe-specific chromosomal patterns are assigned to Meconematinae: 1) In Phlugidini, the X chromosome is metacentric and the largest chromosome of the karyotype; 2) In Phisidini, the X chromosome is telo/acrocentric, and largest element only in species with exclusively telocentric autosomes; 3) In Meconematini, three genera have an acrocentric X element and members of Xiphidiopsis Redtenbacher, 1891 exhibit a metacentric X chromosome; 4) The Australian Phlugidini showed 2n♂ = 29 and the Neotropical P. proxima 2n♂ = 27; 5) Phisidini, except one species, is characterized by lower diploid numbers (2n♂ = 19, 21 or 23); 6) Meconematini, except one presumed parthenogenetic species, is characterized by higher diploid numbers (2n♂ = 33, 31 or 27). No telomeric interstitial sites were observed, indicating a possible ancient chromosome fusion in the origin of the P. proxima karyotype