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I believe, about thirty years ago; and a valuable work, published in 
1903, asserts the Large Blue is extinct everywhere except in North 
Cornwall. But now a number of facts, all of the highest interest, 
have been discovered by Mr. Frohawk. In 1896 he watched the 
females laying eggs on wild thyme, carried off the plants, and 
hoped to solve the problem of the life history. Caterpillars were 
duly hatched ; and all went well till the third moult, when they 
refused to feed, and appeared to wish to hide underground, till in 
despair Mr. Frohawk turned them loose. Again, in 1902, he 
went to Cornwall and watched the females laying. Then he 
noticed one fact which contains the key to the mystery. The 
females always chose wild thyme growing on ant-hills. Following 
up this suggestive clue, he succeeded in discovering full-grown 
caterpillars living underground ; and saw that the ants suck off a 
secretion produced by the caterpillars, just as they suck the sweet 
secretion of the aphides, or blight. Both ants and caterpillars 
are probably interdependent ; and if some external circumstance 
should affect the life of the one the other would also suffer. This 
leads me to a consideration of other phenomena also furnished 
by the same butterfly. 
As I mentioned, the Large Blue, formerly common in the 
Cotswolds, disappeared thence about thirty years ago. Last year 
it unexpectedly reappeared in one of its old haunts ; and though 
both last year and this have been most unfavourable to butterfly 
life, the Large Blue has unmistakably re-established itself in 
Gloucestershire. After thirty years’ death it has revived to 
vigorous life. This fact, however inexplicable, is not surprising 
in view of the abundance of rare butterflies in particular years. 
But far more remarkable is a fact concerning the Large Blue 
announced about ten years ago. Ata meeting of the Entomo- 
logical Society the President announced the absolute extinction 
of that butterfly in the favourite hunting-ground, Barnwell Wold ; 
but he added that it had also disappeared from a park in 
Northamptonshire to which the public were not admitted, and 
where it had been abundant. 
Related facts about the Swallow-Tail and Mountain Ringlet 
butterflies were also cited ; also the abundance of the Marbled 
White at Holmbush, near Poynings, in a space only about $0 
yards square. 
Therefore, continued Mr. Davey, the simple walling-round of 
a sacred enclosure where rarities can be safe is not all that Nature 
wants ; and if Nature chooses to produce an abundance she will 
do it. I have drawn my instances from butterflies, but the same 
holds good of plants ; they will be very common when and where 
Nature chooses. And I have come to the belief, though without 
full proof, that if Nature is left to itself the extinct species will 
reappear, but only up to a certain point of development : we may 
aE ey 198 Bae te 
