COLLECTING, REARING AND BIOLOGICAL METHODS 



This chapter does not pretend to give a complete account of all the methods 

 in use for the collecting, preserving, rearing and biological study of the Odonata. 

 This would take up too much space. Ten years' experience in the field has 

 convinced me that many of the more cumbersome methods are best discarded 

 altogether. I shall therefore chiefly confine myself to the methods which 

 I have finally come to employ, as being the best that I am at present aware 

 of; though I shall not omit to mention other methods also, which are used 

 by others, and appear to yield equally good results. 



The Collection. 



The collection must be made the basis of all work on Odonata, be it 

 systematic or biological. Hence it is of the utmost importance that it should 

 be well cared for, and arranged so that the specimens are easily accessible 

 for study. 



Field-Work. The apparatus required for the capture of Dragonflies is 

 very simple. The only necessary articles are a large net and a tin full of 

 paper triangles. A killing-bottle should not be used. For the net, I use 

 the kite-shaped net, in four pieces and a Y ; dimensions 2 feet by 18 inches. 

 This is too large for most Lepidoptera, but is excellent for Odonata. It is 

 also a useful net for "sweeping" bushes and long grass a method which 

 yields many Odonata in the early morning, and on dull days. In tropical 

 countries, I find that the Y gets overheated, so that the joints melt. It is 

 therefore advisable to have several Y's on hand, and have them well strength- 

 ened by a brazier. 



To have really good specimens of Dragonflies, it seems to me to be essential 

 that they should not be killed artificially, but allowed to die slowly. By this 

 means, the whole of the contents of the alimentary canal is excreted in the 

 form of small dry pellets, which can be emptied out of the paper every day, 

 until the Dragonfly is dead. The result is that the colours keep far better than 

 if the Dragonfly is killed with these impurities inside it. For storing the live 

 Dragonflies, a number of paper triangles should be folded up in the manner 

 indicated in the diagram (fig. 181), taking care that the straight edge of the 

 flap comes to the left (for convenience in writing date and locality). These 

 T. D.-F 23 



