A note, on the karyotypic variability in Crocothemis erythraea (Brullé) and C. servilia (Drury) (Anisoptera: Libellulidae)

During August-November, 1973 we have examined the karyotypes of two adult males from Kurukshetra, India, pertaining to these two taxonomically still insufficiently understood taxa (cf. e.g. F. RIS, 1911, Selys Longchamps Colins zool. 13: 529-700; — 1921, Ann. slh Afr. Mus. 17: 145-452). The haematoxylin stained preparations (cf. J.S. YADAV, 1972, Nucleus 15: 57-64) clearly show karyotypic distinctions between the two taxa, though the chromosome numbers are equal (2n d=25, nd = 13, m). Among the spermatogonial metaphase elements of erythraea there is a pair of distinctly larger chromosomes, whereas the others, save for the tris, are gradually decreasing in magnitude. At the same stage of servilia there is but little size variation among the elements other than the m’s. At the erythraea diakinesis a single chiasma occurs per bivalent, while the chiasma frequency is significantly higher in servilia. \neryihraeai.\\t size of the metaphase I m-bivalent is approximately half that of the X, whereas the in and X are similar in size in the corresponding figures of servilia.