It sounds like one of the small grass skippers. Many of them will lay on grasses in lawns like crabgrass. Just did a quick search for what skipper eggs look like and the first one to come up was for a fiery skipper that looked just like that, but I'm sure a lot of them are similar. Below is a link to pics of California skippers, but if you didn't get a good look at the adult it won't be of much help. The best way to know would be to raise it and take lots of pictures. We would all be very interested in seeing them I'm sure. Finding that tiny egg is like finding a four leaf clover! Here is a link that might be useful: http://butterfly.ucdavis.edu/butterfly/common/Skippers

Not an egg sac. Instead a harmless slime mold. Yes, I know it sounds icky. But not a problem for plants or people. Will go away on its own. If you're curious look up "dog vomit slime mold" -- sans quotes.

Giant Swallowtail eggs. Lovely butterflies, but, in certain areas (especially with commercial citrus growers), considered a citrus pest, as their caterpillars, called Orangedogs, can decimate a young tree. We talk about this frequently on our forum, and for most of us hobbyist growers, we try to find a happy middle ground - leave enough caterpillars on our more mature trees to let nature take its beautiful course, but pull them off our small young trees. If you have other host trees or plants in your yard (Rutaceae family plants), you can move them over to those plants if you want. Patty S. Here is a link that might be useful: Giant Swallowtail Life Cycle Photos

I live in on old farm land outside of Chicago. The bug was a greyish-beige and about 1 inch long. I tried to take a picture but she was laying eggs during the night, so none of the pictures came out. It was the first time I've ever even seen what kind of bug it was laying the eggs. I'll keep an eye out...if I ever see one during the day, I'll post a picture.