PREFACE 
Dr. Samuel Johnson remarked “that every author assumes that he can impart 
something to the public, and that if he fails to excite interest he has no real cause 
of complaint to make against fair criticism.” But the importance of a subject 
cannot always be gauged by the interest it excites, for originality consists in 
breaking new ground and exploring untrodden paths. This is the aim and object of 
the pioneer. 
The activit} r of this age tends to the extinction of many species of high interest 
to the zoologist. Wild animals and insects become rare, and perhaps they may 
entirely disappear. The present volume, though admittedly incomplete, is offered 
partly by the assistance of its portraiture and partly as an invitation to others to 
study the economy of a remarkable family of insects. Their unique forms will give 
the microscopic student much food for thought, and repay his investigations as to 
their economies. 
Those who use the camera lucida in conjunction with the microscope are well 
aware that, with its signal advantages, the prism has defects, so far as exact drawing 
is concerned. The projection of the image of an object must proceed from a single 
point, consequently the outer limits of a field of view, seen through a prism, to a small 
extent will be unduly expanded on the paper used for drawing. The object, say of a 
flower or an insect, is not seen all on the same plane, and the eye must accommodate 
itself by practice to allow for the different foci adapted for different depths. 
Again, an insect, if small and unset, must have its limbs fore-shortened, and 
then the drawing may not appear to be symmetrical. 
Allowances will thus be made by critics, who may complain of a want of 
proportion between the two sides of some drawings. This defect might be cured by 
the engraver, but this correction cannot be expected of him, whose task is often 
strictly to reproduce the figures set before him. 
