The band-eyed brown horse fly (Tabanus bromius) is one of several related species that are pests to horses and so, not surprisingly, they are called horse flies. It is the females that bite as they need mammal's blood after mating to enable the eggs to develop. These are large flies and despite looking rather intimidating present no danger to human-kind.
Their larvae can be aquatic or semi-aquatic and even terrestrial provided the soil is damp. They are predatory on other insects and worms and so are pretty formidable creatures! The adults fly from May through to September but are most common later in the summer.
This species has been given the common name of the band-eyed brown horse fly because the eyes have a dark band across them.