DIPTERA. 81 
Réaumur wished to know how it was that very thick syrups, 
and even solid sugar, can be sucked up by the soft trunk of the 
fly. What he saw is wonderful. If a fly meets with too thick a 
syrup, it can render it sufficiently liquid; if the sugar is too hard, 
it can dissolve small portions of it. In fact, there exists in its 
body a supply of liquid, of which it discharges a drop from the 
end of its trunk at will, and lets this fall on the sugar which it 
wishes to dissolve, or on the syrup it wishes to dilute. A fly, 
when held between the fingers, often shows, at the end of its 
trunk, a drop, very fluid and transparent, of this liquid. ‘The 
water poured on the syrup,” says Réaumur, “ would not always 
insinuate itself sufficiently quick into every part of it; the move- 
ment of the fly’s lips hastens the operation ; the lips turn over, 
work, and knead it, so that the water can quickly penetrate it, in 
the same way as one handles and kneads with one’s hands a hard 
paste which it is wished to soften, by causing the water by which 
it is covered to mix with it. This, again, is the same means the 
fly employs with sugar. When the trunk is forced to act upon 
a grain of irregular and rugged form on which it cannot easily 
fasten, its end distorts itself to seize and hold it. It is sometimes 
very amusing to see how the fly turns over the grain of sugar in 
different ways ; 1t appears to play with it as a monkey would with 
an apple. It is, however,-only that it may hold it well in order 
to moisten it more successfully, and afterwards to pump up the 
water which has partly dissolved it.”’ 
Réaumur often observed a drop of water at the end of the 
trunks of flies which were perfectly surfeited with food. This 
drop ascended the trunk, then re-descended to the end, and this 
many times in succession. It appeared to him that it was neces- 
sary for these insects, as for many quadrupeds, to chew the cud, 
as it were; that, in order the better to digest the liquid they had 
passed into their stomachs, they were obliged to bring it back into 
the trunk that it might return again better prepared. 
In order to assure himself directly of the reality of his suppo- 
sition, Réaumur tested the water which a fly, that he says “ had 
got drunk on sugar,” had brought back to the end of its trunk ; 
he found this to be sugar and water. Also, having given a fly 
currant-jelly, he observed, after it had sufficiently gorged itself, 
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