This is a female scale with eggs and crawlers (newly hatched scales). I pulled the scale off the apple tree on which I found it and had it on my desk for a few weeks (thus the dust that appears as little strands in the photo). Finally the eggs started hatching, and I had crawlers all over my desk. It took a while to notice them because they are less than 1 mm in length. The mother scale was about 5 mm in diameter. The opening in the scale seen in the photo was caused by my tearing the scale from the tree. This didn't seem to prevent the eggs from developing and hatching several weeks later.

Also see related images: (1) (2) (3) (4) (5) (6)