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two bottles I have taken about sixty winged individuals, and out of the 

 third none. 



It naturally occurred to me, when I found so many winged forms 

 appearing in the bottles, and when I remembered that the members of the 

 Anti-Phylloxera Commission informed me that the winged form had 

 seldom, if ever, been found in Portugal, and that presuming their search for 

 the winged form had been diligently made, though without success, then 

 that the circumstances in which the insects found themselves in the bottles, 

 though so contrary to natural circumstances, yet were apparently very 

 much more favourable to the development of the winged form than were 

 the natural conditions. 



What, then, is the difference, or at least most marked obvious diiference, 

 between the natural and artificial conditions ? I think it will be admitted 

 that want of food is the characteristic of the artificial, and abundance of 

 food that of the natural conditions. Perhaps it may be thought that the 

 following experiments to some extent justify the conclusion to which I have 

 referred : — 



Experiment No. 4, Bottle A. — June 29th, 1885 : Placed vine-roots, 

 plentifully populated with Phylloxera, in a glass pickle-bottle, corked 

 loosely, and half-filled with the dry argillaceous soil, in which the vines 

 grew. July 9th (that is, eleven days afterwards), a winged form appeared, 

 and every day, until about the 17th, three or four fresh winged forms 

 appeared, crawling up the neck of the bottle. The roots were quite dead 

 when the first winged form appeared, and were becoming mouldy. A few 

 days after the first winged one appeared many young ones were crawling 

 up the neck of the bottle, apparently searching for food, as they otherwise 

 have a great objection to the light. 



Experiment No. 5, Bottle B. — August 23rd, 1886; Circumstances 

 similar, but less soil was included. On the 28th (that is, five days after- 

 wards) two winged forms appeared, and every day since, up till about the 

 7th September, a duration of ten days, some three or four more winged 

 forms appeared. Since then an occasional one or two appeared, the last 

 being on September 20th. Altogether, out of Bottle A some twenty-five 

 have been taken, and out of bottle B some thirty-six. 



Experiment 6, Bottle C. — In order to make a different test, however, 

 on August 23rd, same date as relates to bottle B, I placed phylloxerated 

 vine-roots in a longer or higher bottle, and, instead of putting a little 

 soil in it, I almost completely filled it with earth and roots ; but up to this 

 date (October 9th) no winged forms have appeared. I have twice taken the 

 roots out of the bottle to examine them, and found numerous insects, as 

 well as eggs, the former apparently quite healthy and active, but they 

 appear to have left the small rootlets which they usually inhabit, but which 

 are now quite dry, and have taken to the thicker or main roots, which in 



