http://www.learner.org/jnorth/tm/monarc ... Facts.html
A Look at the Life of a Monarch Caterpillarhttp://www.nebraskawildlife.org/ww-how% ... 20eggs.htm
"To find an egg, look for common milkweed plants and check the underside of the leaves, starting at the top of the plant and moving down. Females try to lay eggs on new, young plants, so look especially for those. However, eggs have been found on old plants, too, so check them all.
Eggs are the size of a pinhead, cream colored and oval shaped, and are noticeable sticking out on the underside of the leaf. The eggs have ridges that are visible through a magnifier, so you can verify what you have found. Strip the leaf off the plant; the plant will re-grow from that spot...."http://www.raisingbutterflies.org/the-monarch/
This website has video and incredible pictures.
When I went out looking on Saturday this week, I looked at milkweed that look tender. I ended up cutting back some of the milkweed so that it would regrow for those Monarchs laying in the fall. The cold weather pushes them north and some of them are still gravid (pregnant). I looked over the leaves for eggs and tiny larvae. I used 2.50 magnification glasses and those help to see those very tiny caterpillars.