Last week, while I was harvesting fresh maple flowers for my carpet beetles, I noticed a couple of silvery-brown lumps on the underside of a leaf, so I cut that, too. They turned out to be tiny fat beetle-like insects, decorated with four neat rows of studs, each with its own blond hair. They were stuck firmly to the middle vein of the leaf, and didn't respond to tickling with a paintbrush. Dead, dormant, or in the middle of some buggy process? I couldn't tell.
I put the piece of leaf into my little viewing tin, where I could watch and see what happened next. Later on, I had a better idea, and looked over the tree until I found two more leaves with the sleeping bugs; these leaves I harvested with stems, and put them in water in a small aquarium with a good lid.
These "beetles," like the first two, were also lined up on the central vein of their respective leaves.
I've been watching all week; nothing changed until tonight, when I noticed that one of the tinned bugs had a big hole in the rear abdomen:
A tiny fly was flitting around in the tin. I checked the aquarium; sure enough, both bugs had holes in more or less the same location. And a tiny fly raced up and down the walls.
The flies were very small, very fast. I managed to photograph one:
The other, the one in the tin, I trapped (it took me a while) and dumped in a container where a lame spider was resting; he woke up and caught it in less than a minute.
So what has been happening? Were these bugs parasitized by the flies before they settled on the leaves, or afterwards? Or are they a previous stage of the flies themselves? (This doesn't seem possible, but I keep running into "impossible" things.)
Help! I don't even know where to start looking for these. Any and all hints, suggestions, wild ideas are welcome.