Which of the following ornamental insects are classified as leaf miners?

The boxwood leafminer is classified as a leaf miner because its larvae feed within the leaf tissue of boxwood plants. As they consume the plant material, they create distinctive tunnels or mines inside the leaves, which can lead to the characteristic symptoms of damage such as yellowing, browning, or distortion of the foliage. This behavior is typical of leaf miners, making the boxwood leafminer a representative example of this group of insects.

In contrast, the other insects listed do not engage in mining behavior. Fleas are external parasites that feed on the blood of mammals and do not affect plant foliage. Sod webworms are larvae of certain moth species that typically feed on grass blades at the soil level and do not mine leaves. Similarly, chinchbugs are known for feeding on grasses and can cause damage to lawns, but they do not create leaf mines. Thus, the boxwood leafminer stands out as the only option that fits the definition of a leaf miner.