DRAGONFLIES FOR THE CABINET. 143 



What bad best be done in the case of all the larger species — 

 large enough, that is, for easy manipulation — is to eviscerate 

 them and then dry the shell, having stuffed it with cotton-wool, 

 or not, according to the fancy of the operator. The insect 

 should first be fastened down on its back on a sheet of cork, 

 with very fine pins at the thorax and last abdominal segment 

 near the appendages. Then with a pair of sharp-pointed scissors 

 a slit must be made from the second (third in the male) segment 

 to the eighth, thus leaving intact those bearing the genitalia. 

 Now with a pair of fine-pointed forceps the contents of thorax 

 and abdomem must be carefully removed. Usually most of this 

 comes away at once, at any rate from the thorax. If not, while 

 the rest is being removed, great care must be exercised lest the 

 inner surface of the shell should be damaged, for on this in many 

 cases is to be found the pigment to which the colouring is due. 

 This is all. The abdomen may now be filled with a very little 

 cotton-wool, or it may be dried as it is. The markings will now 

 remain, and the colours to a greater or less extent, sometimes 

 almost perfectly, and, of course, there are other elements of 

 beauty besides colour. At any rate, a cabinet of dragonflies 

 which have been so treated makes as fine a show as a cabinet of 

 butterflies and moths. 



If the preservation of colour is sought for scientific purposes 

 only, the dragonflies should be put in good spirit, where their 

 colour usually keeps excellently, except perhaps that of the 

 blue-powdered species such as Libellula deyressa. Indeed, it 

 has been suggested that the small species which cannot be 

 eviscerated should be put in spirit for some time, and then be 

 relaxed and set. It is doubtful, however, if this is so successful 

 a method as was supposed, and specimens dried in spirit are 

 often very difficult to relax, especially if they are not thoroughly 

 mature. 



Just as with Lepidoptera, dragonflies that have not been 

 eviscerated are liable to grease, with the same dire effect upon 

 their colours, and this grease it does not seem so easy to remove 

 with solvents such as benzine, or at any rate its effects are 

 more permanent. Mould, mites, moths, and beetles must be 

 guarded against by the use of naphthaline and by the other 

 ordinary methods. 



Usually the colours of the following British species keep 

 excellently, often even without eviscerating : — males of L. 

 depressa, L. fulva, Orthetram cancellatum, and 0. ccerulescens ; 

 both sexes of Cordulia anea, Somatochlora metallica, S. arctica, 

 Oxygastra curtisii, Cordidegaster annidatus, Gomphus vulgatis- 

 simus ; many examples of j^Eschna mixta, /E . juncea, M. cyanea, 

 ^. grandis, and ^E. isosceles. But individuals in this last 

 genus vary in this respect, and those seem to keep much better 

 which are caught late in the season. The two beautiful species 



