96 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



were sealed with a ring of cementing substance like white zinc cement 

 or gold size, but it was found that mounts that had been made a few 

 years were badly damaged through the evaporation of the water in 

 the glycerine jelly. It was necessary to remount all specimens pre- 

 ^ served in this way. Canada balsam is now used and it is found that 

 by attention to some details sufficient contrast can be secured. 



Specimens to be photographed should be cleared and "posed" with 

 unusual care, all foreign material, as dust and disintegrated tissues 

 from within the body, being carefully excluded. The writer clears 

 specimens by boiling in caustic potash solution in a small, shallow, 

 porcelain dish, replacing from time to time, with a finger-bulb pipette, 

 the water that boils away. The cleared specimen is taken up with 

 a pipette and dropped into filtered water in a clean vessel. From 

 the water it is passed through two or three graded alcohols which leave 

 the empty body wall in an expanded condition. For the best results 

 it is sometimes desirable to pass the specimen through two or three 

 graded alcohol-clove oil mixtures. The specimen is taken up in a 

 drop of the clove oil and placed on the slide and as much as possible 

 of the oil is removed with small strips of bibulous paper. Care 

 must be taken at this point not to introduce dust or threads from the 

 paper. A small quantity of thin, filtered xylol-balsam is added and 

 a number two, half-inch, circular cover-glass is applied. Excep- 

 tional care should be taken to secure a thin mount, thus making it 

 easier to bring all parts of both the ventral and dorsal surfaces into 

 focus under high magnification. 



The Set Up. — Our first negatives were made with a home-made de- 

 vice consisting of a slotted board fastened in a vertical position to a 

 low platform on which the microscope was placed. An extra lens- 

 board in the front of the camera to which was attached a light-proof 

 sleeve which dropped over the barrel of the microscope was found to 

 be effective in making a light-proof connection between the camera 

 and the microscope. This sleeve allowed sufficient play for focusing 

 the microscope. Such a set-up can be secured with very little cost 

 and if vibration is prevented as good negatives can be obtained as 

 with a more expensive equipment. For convenience the writer now 

 uses a heavy iron stand made by the Bausch & Lomb Optical Company 

 which has two parellel guide rods with a scale on one for recording 

 the degree of extension of the bellows. Our stand has extra long 

 guide rods, made to our order for use in other work. This has been 

 found to be very satisfactory and with the various conveniences at- 

 tached, one can work much more rapidly. Nearly all of our insect 

 and flower photography is done with this stand and our various 



