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AND BIOLOGICAL METHODS 



355 



convenient for handling the insect without touching it with the forceps. 

 In setting, a flat board must be used, with a groove deep enough to allow the 

 body of the insect to be placed at least half-way up the pin. Uniformity 

 of plan in setting is best obtained by placing the costa of the hind-wings at 

 right-angles to the body, the fore-wings lying just free of it. The tips of the 

 wings should be covered during setting, or they may turn up. Also, in the 

 broad-winged Libellulidae, the anal field of the hind-wings should be raised 

 from beneath by a small slip (fig. 182). 



Fig. 182. A Dragonfly set on a flat board with double strips of transparent paper. 

 Notice the pins supporting the head and abdomen, and the slips placed beneath 

 the broad anal field of the hind-wings. Original. 



The abdomen of a dried Dragonfly is very liable to break in pieces. This 

 is best obviated by the process of ''bristling" before setting (fig. 183). For 

 Anisoptera, I use hog's bristles, such as can be obtained at all curriers and 

 leather-sellers. For Zygoptera, a fine stiff horse-hair is the best. The bristle 

 should be sharpened by a diagonal cut with the scissors. It is then inserted 

 into the thorax above and between the mesocoxae, and run carefully down 



Fig. 183. Correct method of inserting a bristle. In A, the point of the arrow 

 indicates the point of insertion. In B, the bristle is run through the abdomen 

 as far as b, and is then cut off with sharp scissors at a. Original. 



to the end of the abdomen, care being taken not to damage or displace the 

 appendages, and a small allowance being made for shrinkage during the process 

 of drying. The bristle is cut off close to the thorax with sharp scissors. The 

 head and prothorax do not require bristling; if the head is accidentally 

 knocked off, it can easily be replaced. 



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