Earwigs. They like to hide in moist shady places like mulch and under garden ornaments etc during the day. They go after decaying matter, other bugs and greens. They completely ate or made swiss-cheese out of many of my young plants/seedlings and ruined many of my Datura flowers this spring/early summer. You can try taking a old piece of hose abt. 20" long and lay it out near where the damage is occuring in the evening...check during the day and dump any earwigs in a soapy bucket of water...moistened crumpled up newspaper works too. Vera

Looks like the Thyreocorid/Negro bug. http://bluemountainsconservancy.org/education/bookoflife/Corimelaena_spp.php

When I wrote repeated applications, I wasn't referring to neem oil specifically. For some pests, control is not necessarily a single application for an entire growing season, or even the following month. Do not use stronger solutions or more frequent applications than is on the instruction label. If one type of control does not seem to be working, you can try a different one. Insecticidal soap would be a safe alternative. But that too will require repeat applications since you noted that aphids are a reoccurring problem on this plant. Your plant's infestations appears to be rather mild. A squish/wash-off would be a good start, then follow up in a few days with insecticidal soap to try to keep them from reestablishing a colony. Another thing that can help is to control the ant populations. Ants often like to "farm" aphids.

It`s some kind of leaf hopper most are harmless though some kinds can carry disease but usually not a citrus diease. Your tree does look like it has or had a pretty bad case of spider mites. Get a strong magnafying glass and take a look at the underside of a leaf. Then look up images of spider mites and see if you have em. Horticultural oil works well against them. May need to treat a few times to get them under control.