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tated with about an equal quantity of water, it sinks to the 
bottom coloured pink-red by the Aphideine, whilst the su- 
pernatant ether is of pale yellow colour. On evaporating 
this to dryness, and dissolving in bisulphide of carbon, the 
yellow solution gives a spectrum without any decided ab- 
sorption-bands, and seems to be coloured by a substance like 
that occurring in the fat or wax of other insects. If, how- 
ever, similar living Aphides are crushed up in a test tube, 
kept in that state for a few minutes, and then treated with 
ether, on agitating with water it subsides almost colourless, 
whilst the ether is coloured deep yellow, and its: spectrum 
shows two well-marked absorption-bands in the blue. When 
this solution is agitated with water, no colour is dissolved 
from it, but on adding a little ammonia the greater part of 
the colouring matter passes to the water 4n the alkaline 
modification, of orange colour, giving two well-marked ab- 
sorption-bands between the blue and the green part of the 
spectrum, corresponding exactly to the two bands in No. 2, 
fig. 1, which are nearest to the blue end. On adding a little 
citric acid that on the green side is removed, and another 
developed still nearer to the blue end than the one which 
remains nearly in the original position. If the crushed 
Aphides are kept longer and treated in the same manner, we 
obtain a spectrum with three bands, analogous to No. 2, 
fig. 1; and after they have been kept crushed and damp for 
half a day, the spectrum shows only two bands, which lhe 
so much farther from the blue end than in the former that 
the band nearest to it in this case almost coincides with that 
farthest from it in the other. On agitating this solution with’ 
water and a little ammonia, the colouring matter is deposited 
as a pink layer between the ether and the water, the 
alkaline modification of this substance thus differing from 
that of the former in being insoluble in water as well 
as in ether. Separating it and mixing in alcohol it gives 
a spectrum with two well-marked absorption-bands in the 
green and green-blue, corresponding exactly with the two 
bands in No. 2, fig. 1, which lie towards the red end; and 
on adding a little citric acid the band in the green disappears, 
and another is developed in the blue. There is thus good: 
evidence to show that the variation in the relative intensity 
of the bands in spectrum No. 2 of fig. 1 is really due to a 
variable mixture of these two substances. Both are of yellow 
colour when the solution is neutral, and when dry are of 
waxy consistence. They are manifestly formed by an altera- 
tion of the original Aphideine, and therefore it may perhaps 
be well to call the former Aphidiluteine, and the latter Aphi- 
