Abstract
A unique karyotype 10II+X+y1+y2+y3+y4+y5+y6 is described in the Alticide beetle, Asphaera daniela Bechyné. Despite lack of pairing between the sex chromosomes, their orientation in M I is always , and segregation X—(y1+y2+y3+y4+y5+y6). Clumping-together of all y's in PM I appears to facilitate their orientation as a unit. The number of y chromosomes seems to have risen by accumulation, coupled with a reduction in size.