This is a cicada exuviae, which is the empty shed skin as it molted into adulthood. They will have a split down the back (which is barely visible here) as well as some of the white internal stringy-looking filaments that result from molting. Live cicada nymphs will be crawling, and any that died would still be intact and not the papery husk of shed skins.

We can't identify the other insects; they don't have enough distinctive features visible yet, and do not look like adults (wings are not fully developed). They appear to be nymphs of true bugs though (order Hemiptera), not beetles (order Coleoptera), since immature beetles are grubs and look quite different than the adults. There are a couple beetle families whose adults have very short wing covers (elytra), but the body shape of the pictured insects does not fit with the characteristics of those beetles.

Miri

Thank you so much. One more question, could the little yellow bugs be shield bug nymphs? There seemed to be a lot of them.

Possibly, we can't really see enough detail in the dorsal (top-down) view of the insects to be more certain. A number of true bug species feed on seeds, piercing the seed pod and ingesting juices from inside the developing seeds, so that might be why they are congregating on the spent flower stalk in the photo.

Miri

I will check another picture I have.

Does this picture help with the identification?

Thank you for the additional photo.

This insect is a stink bug (also known as shield bug) nymph (immature), most likely the species Cosmopepla lintneriana, based on its coloration. This species has the common name twice-stabbed stink bug because once it molts (sheds its exoskeleton) and reaches its adult stage it has a black body with two distinct red markings on the back. Here is a link with more photos of this species: https://www.inaturalist.org/taxa/82832-Cosmopepla-lintneriana. 

Twice-stabbed stink bugs are commonly found in Maryland and throughout North America. This stink bug feeds on plant juice with its straw-like mouthparts from a broad range of different plant species. Stink bugs cause minimal plant damage and do not significantly harm the plant's health. These insects are a natural part of our environment with many predators and parasitoids that feed on them. 

Very cool finds! 

Thank you so much for the info! Fun to know