Insect Identification!

I was applying some thuricide this morning to control a caterpillar outburst on my lettuce beds. I noticed an abundance of tiny wasp like insects were also paying attention to my lettuce, but not the other plants. They would land on a leaf surface and inspect or clean the surface before moving to another plant. While I didn't get a photo, I'm hoping someone can identify the wasp/fly from my description.

They range in size from less than 1/4" to just under 1/2" long. Their abdomens are primarily yellow in color with six or seven thin black stripes horizontally across the abdomen. They don't seem to pay any attention to tomato blooms so I assume they are not pollinators. I'm hoping they are some variety of predator wasps. I haven't noticed any aphids or thripes or leaf miners on my plants and I'm curious if the wasps may be helping control them.

It's still to early in the spring for my normal control insects to appear. I haven't seen any spiders or ladybugs or lacewings yet.

Thanks

Ted