26 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



can be used horizontally or vertically (PI. 1, fig. 1). The majority of 

 our insect photographs are made with the camera in the vertical posi- 

 tion, A 5 X 7 view camera and a home-made camera, which will be 

 described later, are used on this stand. The lens used for the most 

 of our photographs is an anastigmat of 4|-inch focus. The short 

 focus lens has the following advantage over one of long focus for this 

 work, (1) greater depth which increases as the focal length decreases 

 and which, of course, is most marked in the micro-tessars ; (2) the 

 shorter belloWs required and the shorter working distance in ma£ing 

 photographs from natural size up to four or more diameters. The 

 following figures illustrate this point. In photographing objects 

 natural size with the 4|-inch lens, the distance from the focusing screen 

 to the center of the lens is 8j inches. The working distance is also 

 8 J inches, making a distance of 16| inches from the ground glass to the 

 object. Comparing an 11-inch focus lens, for example, the distance 

 from the ground glass to the object is 44 inches. In photographing 

 at two diameters, the total distance with the 4|-inch lens is 18 9-16 

 inches against 49| inches with the 11-inch lens. In fact, the short 

 focus lens is the key to the simple oufit which we use. 



The specimens to be photographed are placed on a piece of fine ground 

 glass with the ground surface up. The glass is supported on a frame 

 which carries the background and can be raised or lowered. With the 

 background at the proper distance below the ground glass, there is 

 practically no trouble from shadows. The ground glass does not 

 show reflections from the lens and metal parts of the camera, as is 

 often the case with a plate glass support. 



A 48 mm. micro-tessar lens is used for making enlarged photographs 

 of small specimens, and with the 22-inch extension of the view camera, 

 linear enlargements of ten times can be made. 



The most of our exposures are made by daylight, white cardboard 

 reflectors being used to illuminate the dark portions of the object. 

 There is no doubt that the use of artificial light is advisable, especially 

 when the natural light is poor, but it requires more or less skill in 

 arranging the reflectors in order to obtain an even or pleasing illumina- 

 tion of the subject. The writer has used flash-light powder, without 

 any special apparatus, in photographing insects when the natural light 

 was not sufficient to make the exposure. About a teaspoonful of 

 flash-light powder was placed on a sheet of tin slightly above and about 

 two feet from the object. A large white cardboard reflector was ar- 

 ranged just back of the powder and similar reflectors were placed near 

 the object, on the side opposite from the flash. The object was focused 

 in the usual way and the lens stopped down to f. 16, a match on the 

 end of a stick lighted, the cap removed from the lens, and the powder 

 immediately touched off. 



