On Thursday I checked the eggs and noticed that they weren't eggs anymore, they were moving threads.
They were extremely tiny. This detail was invisible to the naked eye. They were about 2-3 mm long and 0.5 mm thick. Their locomotion was immediately discernable. They moved in the classic "inchworm" style. In the next photo, not only can you see one hatching from it's egg, but you can also see the classic inchworm locomotion in the upper right corner.
It turns out that all "inchworms" are larvae of geometer moths--moths of the Geometridae family--Latin for "Earth-measurer," since they measure it as they inch along. I really wanted to keep a few to watch the complete cycle, but I had no idea what to feed them, and caterpillars can be plant specialists. I have since learned that in Tucson some geometers feed on the hop bush, which Erik has planted in our back yard. Since I didn't know what to feed them, I figured they would have the best chance at life if I put them outside. I placed the diaper back where I found it on the patio. A few hours later my mom was hanging out laundry and saw that the ants were carting the hatchlings off one-by-one! Sigh... The insects are having their end-of-summer wars right now.
Now it makes sense that the eggs were geometer moth eggs. I frequently find adult moths resting on my laundry, especially if I left it on the line over night. Originally I thought that the eggs were laid on the diaper when it was left on the patio, but now I believe the eggs were already there when I took it off the line, I just didn't notice them. Here's what adult geometer moths look like:
Turns out there are 26,000 species of geometer moths in the world! That's over three times as many as all the species of reptiles on the earth! In just one family of moth! There are 400 species of geometer moths in Southeastern Arizona and almost 2000 species of all moths.