48 THE GENERA AND SPECIES OF BRITISH BUTTERFLIES. 
Bardolph Fen in Norfolk. So active has been the pursuit of this beautiful insect during the 
last twenty years, that, as above stated, it is now sought for in vain in the haunts but recently 
so brilliant with its metallic hues towards the close of each summer. It is thought, however, 
by some entomologists that it may reappear in some favourable season, as insects occasionally 
do, in a mamner which has not been satisfactorily accounted for. It is possible, by a provision 
of nature, that a certain reserve of eggs remains unhatched for long epochs, to guard against the 
extinction of species by unfavourable seasons; but whether from this or other causes, it is 
certain that species do occasionally disappear for a time, to be found again at some subsequent 
period. It has been noticed by Lacordaire that in common species of Lepidoptera, a certain 
portion of the eggs frequently remains unhatched the first season, which, so far from being 
barren, as generally supposed, produced Caterpillars in the following year—and therefore it is 
possible that in some cases the vital principle may remain dormant for longer periods. 
Mr, Bond, who has frequently chased the C. dispar on the wing in the Fens of Cambridge 
and Huntingdon, says, “It is difficult to capture, seldom affording an opportunity for a second 
stroke of the net if the first have been unsuccessful.” This, however, is of little consequence to 
young collectors, as matters stand ; for it seems they are not likely again to have an opportunity 
of exerting their skill in the capture of this coveted prize of the British Lepidopterist. 
