Jerry Powell's Checklist of the Lepidoptera Recorded on Santa Catalina Island lists these Catalina Cherry (Prunus ilicifolia) leaf miners simply as Stigmella. In Moths of Western North America, however, he refers to these Catalina Cherry leaf miners that occur on the Channel Islands as Stigmella braunella, and notes that the mines are conspicuous and much larger than most other Stigmella mines, which is consistent with the many Stigmella leaf mines I've observed on this plant.