The family Ægialitidæ, then known by but one species, was placed by Dr. LeConte (Classification of the Coleoptera of North America, p. xxxvi.) in association with those Heteromera having the anterior coxal cavities closed behind. This structure is also assigned to Ægialites in the detailed account of the insect on page 388 of the same work. Dr. Sharp, in his recent treatise on insects (Cambridge Natural History, Vol. VI., p. 265), speaks of the anterior coxæ as being “completely closed in,” while Dr. Geo. Horn, though dissecting a specimen for a study of the mouthparts, seems to have overlooked the coxal structure, or he would certainly have alluded to it in his notes on the genus (Trans. American Ento. Soc., XV., p. 27). In view of the statements in the books, I was surprised, a few months ago, by the receipt of a letter from the Rev. J. H. Keen, in which he asserted that the cavities of the anterior coxæ are open behind, as in indeed the case. Mr. Keen's observation is of great importance, in that it opens the way to a proper appreciation of the systematic position of the insect.