Hiatomyia cyanea
Hiatomyia cyanea, the azure deltawing, is a rare species of syrphid fly observed in the northeastern United States. Hoverflies can remain nearly motionless in flight. The adults are also known as flower flies for they are commonly found on flowers from which they get both energy-giving nectar and protein-rich pollen. The larvae are unknown. References

Diptera of North America
Hoverflies of North America
Rhingiini
Insects described in 1896