Primitive Minnow Mayfly: Siphlonurus

I found this mayfly in my backyard. Mayfly larvae live in water and we live near a river so I'm sure that's where it originated.

photo taken August 2014

Common Name: a type of primitive minnow mayfly
Scientific Name: Siphlonurus securifer
Classification:
     Kingdom: Animalia (Animals)
          Phylum: Anthropoda (Anthropods)
               Subphylum: Hexapoda (Hexapods)
                    Class: Insecta (Insects)
                         Order: Ephemeroptera (Mayflies)
                              Suborder: Pisciforma
                                   Family: Siphlonuridae (Primitive Minnow Mayflies)
                                        Genus: Siphlonurus
                                             Species:  I think it's likely a securifer, but I'm not certain.

photo taken August 2014

You can tell this one is a male because its eyes are so big and its front logs are so long.

photo taken August 2014