A PRIMITIVE COCCID CHROMOSOME CYCLE IN PUTO SP

¹ Department of Zoology, Columbia University, New York

A primitive chromosomal cycle possibly archetypal for coccids is reported for Puto sp. of the family Pseudococcidae. There is no hermaphroditism nor any cytological evidence for parthenogenesis. The diploid chromosome number is 14 in the female, 13 in the male. Somatic mitosis is of the type characteristic for chromosomes with diffuse kinetochore. Meiosis is regular in both sexes. In the male it can be demonstrated to adhere to the coccid-aphid type, with: (a) the first division equational for non-crossover regions; (b) separation of chromatids and their secondary pairing during interkinesis, and (c) segregation of non-crossover regions in the second division. An XX -female, XO -male sex determining mechanism is present. Quadrinucleate spermatids are formed. This is the only coccid thus far reported with a simple and orthodox meiosis in both sexes.