A useful illustration of the life-cycle of the Eastern Dobsonfly, Corydalus cornutus, from Walsh and Riley, The American Entomologist vol. 1 #4 (1861), figs. 56-57, pp. 61-62 (Biodiversity Heritage Library link).
a-larva
b-pupa
c-adult male
d-head of adult female
right (unlabeled, enlarged compared to other illustrations) - eggs on vegetation

The description of the eggs is interesting (link):

The eggs of the Hellgrammite Fly (Fig. 57) are oval, about the size of a radish seed, and of a pale color, with some dark markings. They are usually deposited in a squarish patch upon reeds or other aquatic plants overhanging the water, whence, having hatched out, the young larva finds a ready passage into the element which it is destined to inhabit until the end of the following spring. We have known patches of eggs to be deposited upon the windows of a floating daguerreotype gallery on the Mississippi river.