There is a leaf-mining beetle which infests black locust trees but feeds also on soybeans and other legumes. Each tells a tale of the life history and hungry wanderings of a larva from the time when it hatched, and perhaps as small as a pinpoint, until it became fully grown. Then, in many species, it becomes a pupa from which the adult insect emerges. In others the larva emerges and drops to the ground where that transformation takes place. Serpentine linear mines commonly resemble the aimless crawls of a child with a pencil but increase in width until, at the end where the larva pupated, there is an enlargement like the head of a snake.
Some mines flare suddenly from the starting point and are trumpet-shaped.
In blotch mines the larva feeds around and around instead of straight ahead. The type of mine, and the kind of plant upon which it occurs, gives us a clue to the identity of the insect that made it. We do not know how many species of leaf miners there are. All of them are very small. And there's never a leaf or a blade too mean To be some happy creature's palace.