Look in the glass shade. You'll see some dead insects that were attracted to the light. They're usually well preserved, if a little bleached from the incandescent bulb. Sometimes there are a few hundred or even a few thousand mostly tiny insects. The latter is certainly the case in this photo.
What you are looking at here is the pile of insect remains after I picked out all the whole beetles (excepting the large ladybugs), but it looked a lot like this before I picked them out. In terms of count, I suspect the small homopterans (leaf hoppers) are the great bulk, but there were a few moths and caddisflies, a lacewing or two, some tiny hemipterans, an assortment of flies -- mostly small ones -- and an estimated 400 whole beetles (!!), which is what I was after. Also, dining on the dearly departed were one dermestid beetle larva and several 1mm-long booklice
This batch came from the glass shade of a ceiling light that was on a customer's screened porch, which probably led to the insects being predominantly small -- small enough in many cases to pass through the screen.
For bugguide editors whose interest extends beyond beetles, I have left the above shot large so it can be zoomed in on (only editors can do this) and searched for items of interest.
For beetle fanciers like myself, I've grouped my coleopteran gleanings by family or size if unknown. I can see from my photos that some specimens wound up in the wrong pile.
Although bugguide is best known for photos of live terrestrial arthropods in nature, my hope here is to dramatically demonstrate that anyone who wishes to add new species to their collection of photos of specimens might do well to examine the shade contents next time they change a bulb.
Beatriz Moisset has suggested unlinking the images in this set and including them instead as thumbnails: