Abstract
The chromosomes of 5 species of beetles have been studied in male germ cells with particular reference to the number, morphology, and behavior of chromosomes and the sex-determining mechanism. The chromosome numbers (2n) in spermatogonia are as follows: Heteroderus macroderus Cand. 19; Pheropsophus catoirai Deg. 35; Mylabris thunbergi Bill. 22; Anomalia dorsalis Fab. 20; and Batocera rubus Linn. 20. The X-chromosome in H. macroderus is always found lying off the plate at the first metaphase.