Well, that was something. I'm about to head into the kitchen to make some lunch, and I notice a fly. A lot of flies. More than should be indoors. So I open up the windowshade to see if I've left the window open.
I know that bugs get trapped in my window when I close the glass pane in front of the screen. But this is the first time that one has laid eggs in there. I guess they fed off the remains of other dead bugs that have fallen to the bottom of the window. Luckily, the majority of them did not get through the screen. Those I was able to remove with a window fan. After that, there was a long period of fly swatting. My cat was vocally interested in the process, but not enough to help.
Afterwards, I remembered that a vacuum cleaner would have been more efficient. I'll have to do that next time. Although it's pretty unlikely that there will be a "next time."