This beautiful beetle is often mistaken for a fly, because it has excellent eyesight, and quickly runs or flies away when you approach. What is it, and why is it in danger?

This is a White Beach Tiger Beetle (Cicindela dorsalis media). They are very fast when running or flying, and they are voracious hunters. They are also declining, and several related species are on the endangered species list. They lay their eggs in the sand near the high water mark, and their larvae, which are also predatory, live in the wet sand. As people develop more and more beaches, their habitat is disappearing. Considering that they eat lots of the small, biting flies that pester us on the beach, having them around is a very good thing.