I have found beetles munching away at the leaves of my trees. They tend to eat at the perimeter of the leaves. We have leaf-footed bugs that suck the sap out of the leaves. They tend to work in the middle of the leaf. The leaf doesn't really curl or show a puncture wound, but it does wrinkle around the bug's incision. Both the leaf-footed bug and the beetles are usually out munching at night. I have also dealt with leaf curlers and spider mites. Both spin a web on the underside of the leaf that either causes curling at the edge or wrinkling in the interior. If you take a magnifier to the underside of the leaf, you might see the bugs that are responsible. Last year I took a two part approach to getting rid of the bugs. One I sprayed with neem oil weekly for four weeks. Secondly, while it rained, I would use the hose with a sharp spray on the underside of the leaves. The buggies don't like being wet, which is why they hide on the underside. I think this was more effective than the neem oil. Neither method was effective on the Beetles or Leaf-footed bugs. I'm not sure if a poison would be more effective, I hunt them at night with a flash light. If you flick them, they hit the ground stunned and then a quick stomp does them in. Its actually kind of good for relieving stress. Your bugs may be different, but you should be able to see them hiding on the underside of the leaf or at night. If you decide to use the neem oil (or any other spray, spray either in the morning or at dusk when it is cooler. ~james.

It looks like a lady beetle larva. They are good bugs and eat plant pests like aphids.

It's a beetle, which narrows it down to thousands of species - try looking for references to the insects of a geographical area you fall within, then seeing what beetles they show as being in that area. I get the same general type appearing seasonally in my area also - it is probably discussed frequently once you find the right sources.

It's a shield bug, aka stink bug or pentatomid. There are many species but they all kind of have that look. Yours could be a brown marmorated stink bug. They're considered invasive pests (although most stink bugs can be problems). Cute little guys though, right?