I needed a picture of a Hellgrammite to send to a buddy. Yours are tops. I have long time experience with the hellgrammite.
We use them as bait for bass fishing. I have seen the adult Dobsonfly and it is larger and broader has a much stronger wing structure than your photos.
I will attempt to take some pictures of some local dobsonfly. The ones that you are showing wimpy.. Some of these hellgrammites are 4 to 5 inches in length.
Nice web site.