Perhaps the most difficult part of the procedure is actually catching the dragonflies, especially in high summer. We leave this part to your ingenuity. Once we have specimens, our procedure is to place them in ZiplocTM plastic bags. Two or three can be placed in a quart sized bag if the bag is folded to prevent the dragonflies from coming into contact with one another. Nearly anything they can grab with their legs will be pulled to their mouth and chewed on, resulting in damaged specimens. Depending on the weather, the dragonflies can be placed in a cool, dark container or placed in an ice cooler (although not directly on the ice). Left in the sun in a bag, the dragonflies will perish quickly. In the laboratory, the bags are placed in the crisper portion of a household refrigerator or in a plastic shoebox on one of the shelves, where they can remain overnight. As a rule, the sooner the specimen is scanned, the better. Although short-term refrigeration has not notably changed the color of the dragonflies we have scanned, our current experience is limited to only 20 or so species. Needham and Westfall (Dragonflies of North America,1954) use dark cages to maintain their dragonflies without noting any changes in color. Dunkle (Dragonflies of the Florida Peninsula, Bermuda and the Bahamas, 1989) notes the deleterious effect of freezing on specimen color and rapid deterioration of the specimens upon thawing. Dragonflies refrigerated for 30 minutes or more are usually sedate enough to scan. They recover within minutes, however, and must either be returned to refrigeration, released or placed in acetone to become a museum specimen (see Dunkle (1989) for the acetone procedure). Short-term refrigeration (four to six hours) does not seem to have a deleterious effect on the dragonflies, and most specimens can last for 24 or more hours.
The dragonfly is scanned by placing it upside down on the scanner bed. To prevent the scanner cover from crushing it, a mousepad with the center cut away is placed around the specimen on the scanner bed. The smaller area inside the cutaway also allows for easier orientation of the specimen, and the pad blocks stray light from the edges of the scanner. The cutaway area must be large enough to prevent the inside edges of the pad from casting shadows on the specimen. The pad used for making these scans has a cutaway area 10 cm by 12 cm and is 6 mm thick. For bigger species such as Anax junius two pads can be stacked.
Two scans of a given specimen will capture much of its color and anatomy. The top scan will capture most of the eyes, all of the wings, and the top of the thorax and abdomen. The specimen can then be placed on its side with the wings folded. On most dragonflies, this will also allow the colors of the face to be seen. The colors of the legs (depending on their positioning) and the sides of the thorax and abdomen will also be clearly visible. With small species such as Perithemis tenera, two specimens can be placed on the scanner at the same time and only a single scan made.