These are the eggs of the Green lacewings. If you see these in your garden, leave them be.
Some Green Lacewing larvae carry dead skins of insects and dead vegetation on their backs.
Found on Beargrass - Nolina microcarpa, early April, mid Spring, zone 9b, Phoenix, AZ, USA
Taken on 7th August 2006, Lincoln UK.
They are attracted to light.
This larva is feeding on caterpillar eggs. I didn't even know it was there until I looked at the enlarged photo. I went out the next morning and every egg was gone.
In my Maine garden
Taken on 15th July 2008. Attracted to light on the outside window.
Taken on 1st June 2008 on the outside window, attracted to light.
September 26, 2006; Phoenix, AZ