Spots appearing on leaves of some plants

[gtnate]

I recently noticed these little black spots showing up on the leaves of my pepper, basil, and mint plants. It looks like insect damage to me, but I haven't been able to find any type of insect infestation on the plants. Does anyone know what it is and if I should worry about it?

[decherdt]

We had a couple of four line bugs leaving that sort of pattern on seedlings, until I found and removed them.