A tad small to be certain. But possibly dead aphids which have been attacked by a beneficial, but very tiny, wasp.

Your "worm" is a flower fly -- it kills aphids.

Thanks for the flower fly ID! Good news.

But no, I'm pretty sure these weren't aphids--no legs. I got very close and saw smooth ovals. Sorry the picture isn't any good. I find lots of critters when I search online for eggs under tomato leaves, but most seem to be in clusters--ladybugs, cucumber beetles, etc. Anyone know of any who lay eggs more distantly from one another on a leaf?

I had those same eggs on my patio tomato plants early in the season. I watched to see if they were good guys or bad guys. It wasn't long before I had solid evidence they are bad. All the leaves they were on yellowed, browned, and went completely crunchy. In no time the plants were stressed.

I don't recall what the garden center said they were. However, a good dousing of veggie insecticidal spray did the trick. I didn't have time to figure out a natural solution. My plants were really getting stressed. (I had to saturate the leaves on two consecutive days.)

My actions did not seem to affect polination.

Good luck!

Erin

Thanks for the input, Erin. I never did figure out what these were--I wish I'd gotten a better picture, or kept the leaf in a jar and watched to learn for myself. I've grown tomatoes for a while now, but this is the first year I've had the time to pay attention to the details and try to figure out what, exactly, is going on in my garden.

I've been lucky so far. I started out with loads of aphids and was getting itchy to spray with soap, but instead planted more sweet alyssum among the marigolds around the tomatoes and crossed my fingers. Ladybug, flower fly, and a few lacewing larvae popped up shortly after the aphids did, and the aphid population dropped off. There are plenty of pinkish-tan aphid mummies too, which does my vengeful heart good. So far only a few striped cucumber beetles and no signs of hornworms yet, though I've found a couple gray-brown 1 1/2" long caterpillars near the tomatoes. I'm going to try to stick with the no-insecticide method this year.