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Book Notice. 
A Preliminary Monograph of the North American species of Trogophlceus ; 
by Capt. Tos. L. Caszy:; Ann. N.Y. Ac. Sci., v. IV, 1889, pp. 322 —383. 
In this paper, Capt. Casey seems to have done good work so far as 
it is possible to judge without actually testing it in collections. The 
characters used seem clear, the tables are concise, and the descriptions 
terse—an inprovement perhaps on former papers where excessive length 
of description was criticised. No sexual characters are used or even 
mentioned, though in many other Staphylinide genera they are of the 
highest value. 66 species are recognized, most of them new, anda 
large proportion of them based on single specimens—a perhaps unavoid- 
able element of weakness, since it is much more difficult to judge of the 
value of characters. In some respects the most interesting part of the 
paper, and one meriting thought, is in the introduction, largely devoted 
to defending the microscope versus the hand lens, and somewhat im- 
pugning the value of results attained by using the latter. Now here an 
element comes in which Capt. Casey himself recognizes, when he speaks 
of ‘‘the novice who has not yet learned to interpret what he sees”—it is 
the experience of the user of either lens or microscope. Behind each is 
an instrument which is much more important—the trained eye of the 
observer—the eye that with a good triplet can count the joints of a 
Trichopterygid antenna, while the untrained user of the compound mi- 
croscope cannot with an infinitely greater magnifying power be sure any 
joints exist. Now I am a believer in the microscope, and I use it con- 
tinually in my work. Ihave hada binocular stand in use for several 
years, and have a very fine instrument for my college work—yet it has 
happened to me frequently that I have taken a specimen from the micro- 
scope and studied it with the lens with much more satisfactory results. 
I saw more and saw it better. Increase in the size of the image does 
not always import increased distinctness of detail. Discretion in the use 
of appliances must be exercised and the man who uses a microscope 
only, is apt to make as many errors as a man using the lens only. It is 
in the interpretation of what is seen, that the errors are made. It is the 
experience of the observer, and his ability to select those characters 
which are of importance, that determines the character of the work : that 
experience which enables a man to recognize specific characters among 
the assemblage presented by any given group of insects—which enables 
him to recognize the limits of variation—which will enable him to dis- 
card striking modifications in many instances as unsafe, and rely upon 
inconspicuous features for specific characters. No hard and fast rules 
can be formulated for the conscientious student: he will be a ‘‘lumper” 
