It's oedema left behind in the path of a warble fly larva burrowing through the flesh of an animal. Nice.
The scientific name for the fly larva inside goldenrod is Eurosta solidaginis.
Another name for the "Crane fly" is the "Daddy long legs"
eggs
Well, larva is like a baby bug, but there are different types of larva. Like beetle larva, fly larva, etc.
the larva of the fly is the stage before the fly.
A caddice is another name for the caddis, the larva of a caddice fly.
Maggot
A caddisworm is the larva of the caddis fly.
no lava can't fly
A leatherjacket is a fish and the name of the larva stage of the Crane Fly, so it is also an insect.
Literally, a gadfly is a fly that bites livestock, esp. a horsefly, warble fly, or botfly. Figuratively it is an annoying person, esp. one who provokes others into action by criticism.