Here is one that I am just not sure about. At first, I thought is was a tangled spider nest, but upon closer examination, I do not think so. Then I thought about hairs - possible but they have a curliness about them that hairs do not usually. Possibly plant fibrous material? I am just not sure. I do know the piece is good sized and looks beautiful.
While some wasps are tough to ID, so are not, this is an ensign wasp, Hymenoptera, Evaniidae - the constriction at the abdomen is a dead giveaway. The larvae of the ensign wasp are parasitic in egg capsules of roaches. The adults are likely to appear in places where cockroaches appear.
Bristletails are rarely found in Dominican amber. The order Thysanura, is characterized by three long tails and long slender antennae. The body is shrimp-like. Thysanura, in particular, may be the direct ancestor of winged insects. There are also 3 or 4 fungus gnats, Diptera, Mycetophilidae. This is a good piece.
Interesting piece. This has a large long legged fly, Diptera, Dolichopodidae (?), an unknown beetle (not sure about this one), two fungus gnats, Diptera, Mycetophilidae and a moth fly. It has some other stuff also. A lot of the animals were caught at the 'interface' of two layers of resin - easily seen in the photo.
Hazy piece that has quite a bit inside it. There is a planthopper , Homoptera, Fulgoridea, with the wings spread - you can even see patterns on the wings that are 20 million years old. Also there is a thrip, Thysanoptera, a fly, Diptera, a female ant , Hymenoptera, Formicidae and a springtail. There is a lot of stuff inside this amber.
If you recognize the wings, then you know that this is a mayfly Emphemeridae. This is a male since the cerci are so long. This specimen with all three cerci intact is very rare. Mayflies are characterized by protruding eyes. Hind wings are small and rounded or very reduced. Mayfly adults enjoy a life span of no more than two days. On the transition from nymph to adult stage, they fly from the surface of the water for mating, but do not feed. They complete their mating process and die after one or two days. This specimen is perfect.
Another good sized piece of amber with a nice spider at the bottom. The shape is good, rather like a thick triangle. There are a number of small en-hydros (bubbles within bubbles) - containing water that is 24 million years old. There is also a fly near the amber. "Waiter, waiter, there is a fly in my amber...."