It is necessary for me to correct a serious error into which I have fallen.At page 165, v. 3, I have described a larva mining the upper surface of leaves of the White Oak (Quercus alba), which seemed to me to answer the requirements of Dr. Clemens'Lithocollctis tubiferella, which also mines the leaves ofQuercus alba. The larva was not removed from the mine, but viewed through the integument.