PHOTOGRAPHY FOR ENTOMOLOGISTS. 193 



Photography for Entomologists {n-itfi two plates). 



By FEEDEEICK NOAD CLAEK. 



When first I took up this work in connection with entomology^ 

 some fifteen years ago, although I could foresee the many applications 

 it would have in every branch of natural history, I did not imagine 

 that it would have been in comparatively so short a time so extensively 

 utilised in our study. At that time photo process work was in its 

 infancy, and the low standard of quality then obtaining was no doubt 

 responsible for a good deal of shortcoming in this respect. It cannot, 

 however, be said that this is the case at the present time, now that 

 photographic reproduction processes have been brought to such a high 

 state of perfection, and are being employed by our best known 

 authorities in every branch of entomology. Some reproductions from 

 drawings and diagrams are excellent in their way, and in many 

 instances are indispensable, but for accuracy of delineation they are 

 not to be compared with the results obtainable by photography. 

 When employed in conjunction with the microscope, as in photo- 

 micrography, its advantages in demonstrating the minute structure 

 or anatomy of insects are obvious. Absence of the " personal 

 equation "is also a point that should not be overlooked. In the 

 study of entomology there is no lack of material or scope for the 

 practice of photography. 



Low POWER PHOTOGRAPHY. — By this I mean the photography of 

 those subjects which require but little or no magnification, as in the 

 case when photographing whole insects or large portions of such. 

 These are frequently too large to be included in the field of the low 

 power micro-objective. In such cases we must use the photographic 

 lens and camera. For large insects a good wide angle or short focus 

 lens is necessary, the required magnification being obtained by camera 

 extension. With objects intermediate in size, between the latter and 

 those that are obviously microscopic specimens, 1 recommend a lens 

 of the "Planar" type. Most opticians now supply lenses of this, 

 type, and they are indispensable for photographing such objects as 

 eggs and the larger structures. They are somewhat costly, but in 

 practice are extremely useful when the object is too large for the field 

 of the low power micro-objective. Besides covering a wide field of 

 view, they give splendid marginal definition, and, what is sometimes; 

 of even more importance, a "depth of focus" which is quite 

 unattainable Avith the micro-objective. I have a Sin. lens of this: 

 type by Watson & Sons, which enables me to do work that, prior to> 

 their introduction, was out of the question. The setting up of the 

 object requires some little skill in order to get the best results. I 

 have in my mind's eye a group of lepidoptera which it is desired to. 

 photograph on one plate for reproduction. The insects should be^ 

 high set Avith suitably long pins, and pinned on slender pieces of cork 

 about an inch long, which latter are fixed Avith sealmg wax or shellac 

 on a sheet of ground glass. The AA'hole is then photographed by- 

 daylight, using a mirror at the back of the ground glass so as to- 

 neutralise any sbadoAvs cast by the insects, should this be desirable. 



Photomicrography. — To produce really good work the microscopist; 

 must be an expert photographer. Many Avbo are old hands with the 

 microscope, when attempting photomicrography, fail solely on account 

 July 20th, 1906. 



