356 



COLLECTING, REARING 



[CH. 



For the process of papering, the paper may be prepared by treatment 

 with a solution of mercuric chloride, or a little dust of naphthaline or thymol 

 may be placed with the insect. A small piece of pith gummed into the head- 

 end of the triangle will serve to keep the two sides sufficiently apart to prevent 

 damage to the head of the insect by pressure. The appendages of the second 

 segment of the male are more easily studied in papered specimens than in 

 set ones. The specimens should be kept in large tobacco-boxes in a dry 

 place, and securely fastened down except when needed for examination. 



Each specimen must of course be labelled with locality, date and name of 

 collector. In set specimens, the label should be placed on the pin upwards, 

 so that it can be read without moving the insect. In papered specimens, 

 the label is either printed on the flap, or on a small slip placed inside with the 

 Dragonfly. 



Naphthaline, thymol, and an occasional dosing with carbon bisulphide will 

 keep the collection clear of the usual insect pests. Grease is very rare on 

 Dragonflies. To my knowledge, it only attacks the larger Aeschninae, par- 

 ticularly Anax and Gynacantha. It can be cured by immersion in powdered 

 magnesia, or, better still, by careful evisceration of the specimen before 

 setting, and re-filling the abdominal cavity with cotton-wool and powdered 

 magnesia. In damp climates, a small white fungus is apt to attack the 

 specimens. This can be removed by treat- 

 ment with an alcoholic solution of mercuric 

 chloride, or with carbolic acid. 



Preservation of Colours. Much has been 

 written on this subject. The pattern, though 

 not the brilliance, of all dragonflies can be 

 preserved, if the insect is allowed to die in the 

 manner already described. For preservation 

 of the bright hypoderm pigments, rapid drying 

 is essential. A collection which I received 

 from Central Australia, and which had travelled 

 for three months per camel-mail, was found to 

 be absolutely perfect in coloration, even down 

 to bright reds and blues. Such was the effect 

 of the hot dry climate ! I find that a dry 

 temperature of 105 Fahr. is the best. At 

 this temperature, a Dragonfly will set in from 

 eight to twelve hours, with all its colours 

 perfect (except only the sky-blues of Agrionidae 

 and the blues and greens of Aeschninae, which 

 are unreliable). For this purpose I have 

 designed the oven shewn in fig. 184, in which 

 the setting-boards are placed along two sides 

 of the oven, face to face vertically, and are 

 held in place by the two ridges on the lid. 



Fig. 184. Drying oven for 

 dragonflies, to take 14 

 inch setting-boards (x^). 

 Original drawing by P. 

 Tillyard. 



