I just finished cutting off a bunch of new growth in one of our orange trees. It was covered in whitefly eggs.
These things always remind me to do more research, and while doing just that I found this neat site . They show good photos of each life stage of the dreaded whitefly.
In the site they also include chemical control, which, of course, I do not advocate...but I include the link here because I found the pest's description and illustrations to be very informative.