No abstract

No abstract

An endemic Puerto Rican Elaterid, Pyrophorus luminosus III., has 17 chromosomes in the male, the meiotic karyoformula being 7 + X1X2Y, or as expressed structurally, 7 + XpneoXneoYp. Xp is heteropycnotic in prophase and differentially argentophilous from prophase to metaphase II. The parachute of a modified shape is only slightly stained by AgNO3 and by Rattenbury's nucleolus staining method.Key words: Elateridae, Pyrophorini, sex chromosomes, sex trivalent.

Although the cytology of the Oedionychina flea beetles is unorthodox in many ways, their karyotypes are conservative in chromosome number and sex chromosome system: typically 2n = 22(X, y); 10 + X + y. Differences between karyotypes are expressed mainly in arm length ratios. This study describes instances where this conservatism is broken and new karyotypes have emerged or seem to be emerging. The cases include distance sex multivalents up to 7x + Y (Asphaera spp. and Aspicela scutata), a full series of autosomal centric fusions: 5 + X + y (Alagoasa equestris), up to 17 B chromosomes (“Al. transparent” and Al. oblecta), and erosion of achiasmate arms (Al. januaria).