One species, Micrurapteryx salicifoliella (Fig. 1), is placed in this genus. The larva is a leaf miner on willow, Salix sp. (Salicaceae). The leaf mine is a flat upperside blotch, initially greenish but later turning brown. When it finishes feeding, the larva chews a hole through the bottom of the mine and exits through it. The cocoon is often spun on the upperside of a leaf, parallel to its long axis. The cocoon is of a flat lozenge shape, similar to that of Caloptilia, but it is more nearly transparent than in Caloptilia, so that the Micrurapteryx pupa can be seen through the upper wall, the central area of which is adorned with many small white flecks. Leaf mines have been collected in central Illinois in early June. Adults occur in mid-late July in Illinois, with a possible second generation emerging in October. The adult is similar in appearance to Parectopa occulta.
Figure 1. Micrurapteryx salicifoliella. Top: adult, reared from leaf mine on willow, Salix sp. (Salicaceae); bottom: left, recently-evacuated leaf mine; right, cocoon.