Size of the eggs?
Flea eggs are very tiny and are approximately the size of a small grain of salt. They are also translucent with a whitish tint, this along with their size make them very difficult to see.
An adult female flea will lay up to 20 eggs at one time and will begin laying after feeding. A flea will lay her eggs right on the dog, cat or other host. The eggs do not adhere to the the hairs of the dog or cat but simply fall off on their bedding or other areas they frequent. Places your pet sleeps, plays or spends anytime can be places the eggs fall off to later hatch.
Time till hatch?
Flea eggs take 2 days to 2 weeks to hatch depending on temperature and humidity. Flea eggs hatch the most rapidly in warm humid conditions. An adult female flea can lay from a few hundred to a few thousand eggs in her lifetime. This explains how flea infestations can grow rapidly and become horrible in a short period of time.