Small Minnow Mayfly  (four photos)
Callibaetis

mayfly
 I believe this is a female Mayfly I found at Bear River MBR.  The females have the coloring on the wings.  © Carol Davis, 4-22-2009

mayfly
This appears to be a male mayfly as there is no coloring to the wings.   Antelope Island -
©  Carol Davis, 9-18-2008

mayfly
I think this one just shed it's skin (exuvia), that's why it looks so perfect and white.  I understand the colors fill in later. 
Below is a mayfly exuvia.  Taylorsville, UT - © Carol Davis 9-18-2008

mayfly
This is Mayfly exuvia I found near my back door. Very cool. © Carol Davis

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