Young Oak

There is a youthful oak tree in front of my house that has a number of branches low enough for me to be able to look for what might be living on them. The tree is about twenty feet tall, which isn't much for an oak tree; I could probably just about span the trunk with my hands. It has a long way to go in life, but for now, its lack of stature means that I get a good view of the bugs on its lower leaves. But there is a lot of the tree that is beyond my visual scope, and I do sometimes wonder how much is going on up there out of view? Because there is a great deal going on at the level where I can see, and that is a small part of the space available in the tree. Sometimes I look at trees and think of them as teeming cities, or individual biomes, or habitats.
Here's what I saw on that tree today:

 Copper underwing caterpillar

 Sawfly larva

 Oak galls (which have insect larvae developing inside them)

This is what it looks like inside, by the way. Fluffier than you might expect.

 Different species of sawfly larva

 This leaf was rolled up into a hideaway by the caterpillar whose head you can just barely see peeking out toward the lower right

 All over the branches were leaves with bits rolled up like this; my brief research tells me that it is probably created by an oak leafrolling weevil. It lays its eggs inside these rolls.

There were ants on the tree, too, and a couple of spiders that you'll see below. Yesterday there were more species of insects on the tree, including the Backyard Bug of the Day.

And speaking of Backyard Bugs of the Day...

Backyard Co-Bug of the Day #1:

 Leaf beetle, species Chalepus walshii

Backyard Co-Bug of the Day #2:

 Katydid nymph

Backyard Co-Bug of the Day #3:

 Scorpion fly, male. It doesn't sting, it just looks like it has a scorpion tail.

Other Bugs:

 Ants on raspberry blossoms

 Crane fly

 These pink speckles appear on the leaves of this tree most years. For a long time I assumed they were insect eggs of some kind, but I think they are actually some kind of fungus.

 Some kind of longhorn flower beetle. It's not alone in that flower cluster...

 There was another beetle in there, too.

 Milkweed leaf beetle:

 Assassin bug with prey, which I think is a sawfly.

This is the first time this shrub has flowered, and I don't know what it is, but it was pretty popular with insects:

 Ants and the aphids they are herding

 Hopper nymph

Looper caterpillar

Arachnid Appreciation:
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These first two spiders were on the oak tree:

Harvestman with a lot of parasitic mites