all images from the pond to date - itsaboutnature.net

Dobsonfly !

Here is a snapshot of a video I did at the "Pond of my Boyhood". As I was gliding down the winding dead waters I spotted a large, winged insect struggling on the water surface. It turned out to be an adult Dobsonfly. You won't see more than one or two of these in your life…if that. This is the adult of the highly valued-for-fishbait aquatic larva called the hellgrammite . Here is link to a good reference:

http://www.fcps.edu/islandcreekes/ecology/dobsonfly.htm

From Invertebrates