PRESERVING OVA, LAEVJE AND PDPJS 133 



It is much to be regretted that the natural colours of many 

 caterpillars cannot be preserved in the blown skins. Some are 

 rendered much lighter in colour on account of the withdrawal of 

 the contents, while others turn dark during the drying. In the 

 smooth-skinned species the natural tints may be restored by paint- 

 ing or by staining with suitable aniline dyes, but these artificial imi- 

 tations of the natural colours are always far less beautiful than the 

 hues of the Jiving larvae. 



Very few words need be said on the preservation of pupae. 

 Many of them do not alter much in form and colour, and therefore 

 they require no special preparation. 



If a pupa has to be killed for the purpose of adding to the value 

 of the collection, simply plunge it into boiling water, and it is ready 

 to be fixed in the cabinet as soon as it is quite dry. 



The empty pupa cases, too, from which the perfect insects have 

 emerged, are often worth preserving, especially if the damage done 

 by the imago on forcing its way out is repaired with the aid of a little 

 coaguline. 



Let all larvae and pupae be preserved in their characteristic atti- 

 tudes and positions as far as possible, so that each one tells some 

 interesting feature of the life history of the living being it repre- 

 sents. Further, enrich your collection by numerous specimens of 

 the various kinds of cocoons constructed by the larvae, pinning each 

 one beside its proper species; and never refuse a place to any 

 object that relates something of the life history of the creatures 

 you are studying. 



