There is one principle that should guide every careful writer, viz., that in any publications whatever, where facts or opinions are put forth, it should always be made clear as to which are based upon the author's personal experience and which are compiled or stated upon the authority of others. We should have no patience with a very common tendency to set forth facts, even those relating to the most common and best known species, without the indications to which I have referred. The tendency belittles our calling and is generally misleading and confusing, especially for bibliographic work, and cannot be too strongly deprecated. On this point there will hardly be any difference of opinion, but I will allude to another question of credit upon which there prevails a good deal of loose opinion and custom. It is the habit of using illustrations of other authors without any indication of their original source. This is an equally vicious custom and one to be condemned, though I know that some have fallen into the habit, without appreciation of its evil effect. It is, in my judgment, almost as blameworthy as to use the language or the facts of another without citing the authority. Every member of this association who has due appreciation of the time and labor and special knowledge required to produce a good and true illustration of the transformations and chief characteristics of an insect will appreciate this criticism. However pardonable in fugitive newspaper articles in respect of cuts which, from repeated use, have become common or which have no individuality, the habit inevitably gives a certain spurious character to more serious and official publications, for assumption of originality, whether intended or not, goes with uncredited matter whether of text or figure. Nor is mere acknowledgment of loan or purchase to the publisher, institution or individual who may own the block or stone what I refer to. But that acknowledgment to the author of the figure or the work in which it first appears which is part of conscientious writing, and often a valuable index as to the reliability of the figure.