Changes in the Fine Structure of the Corpus Allatum Cells in the Milkweed Bug, Oncopeltus Fasciatus

The ultrastructure of the corpus allatum of adult milkweed bugs was studied during the active and inactive period. The inactive gland was removed from female insects sacrificed less than 24 hours after eclosion. The active gland was removed from mated females that produced viable young. These females were from 13-15 days old.The inactive gland has a large number of mitotic figures. Some cells, not in division, have a nucleus with a regular outline, many polysomes and active dictyosomes. Other cells are more electron dense, have nuclei with an irregular outline and many free ribosomes.