Satyrium caryaevorum (Hickory Harstreak) eggs (?)
Carya ovata (Shagbark Hickory) - Arkansas

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eggs on branch

Eggs at base of young tree

Eggs - in base of broken twig

Eggs in bark of trunk
My experience with eggs of Satyrium calanus (Banded Hairstreak) is that they are usually laid singly next to a bud near the tip of a twig, or in an old bud scar near the end of a twig. This leads me to beleive that these are eggs of Hickory Hairstreak in my new yard in the Ozark Mountains of Arkansas (2150 ft.). I should be able to confirm this nest spring, as the eggs were numerous.