I hardly need an apology for presenting from time to time to the entomological public descriptions of galls of Cecidmyiæ, even when I did not succeed in rearing the fly. Such observations, unless published soon, are very apt to be lost; once published, they gradually accumulate and furnish a welcome material for the future monographer. To facilitate reference, I give here a list of my previous publications on the galls of North American Cecidomyiæ