sy LEPIDOPTERA. 175 
This trunk, of which the butterfly makes such good use, is com- 
posed of two filaments more or less long, horny, concave in their 
interior surfaces, and fastened together by 
their edges. When cut transversely, one 
sees, according to Réaumur,* that the in- 
terior is composed of three small rings. 
Consequently, there are three canals in the 
trunk: one central, the other two lateral 
(He. 138). Are all these three used to con- 
duct the juice of flowers into the butterfly’s 
body P Réaumur has made some very in- 
teresting observations on this subject, by 
7 | ral Fie. 138.—Section of a Butter- 
observing a moth which was sucking a lump 7h eee ccm 

of sugar, whilst its portrait was being taken. 
“J held in one hand,” says Réaumur, “a powerful magnifying 
glass, which I brought near to that part of the trunk I wished to 
examine; I was sometimes half a minute, or nearly a minute, 
without perceiving anything, after which I saw clearly a little 
column of liquid mounting quickly along the whole length of the 
trunk. Often this column appeared to be intersected by little 
balls, which seemed to be globules of air which had been drawn up 
with the liquid. This liquid ascended thus during three or four 
seconds, and then ceased. At the end of an interval of a greater 
number of seconds, or sometimes after an interval as short, I saw 
some fresh liquid mounting up along the trunk. But it was straight 
up the middle of the trunk that it seemed to ascend. 
“The Author of nature has given to insects means of working, 
which, though very simple, we cannot divine, and which often 
we are not able even to perceive. Whilst I was observing the 
trunk of our butterfly, between the columns of liquid which I saw 
ascending, there were, but more rarely, times when I saw, on the 
contrary, liquid descending from the base of the trunk to the point. 
The descending liquid occupied half or two-thirds of the tube. It 
was no longer difficult to perceive how the butterfly is able to 
nourish itself on honey, the thickest syrup, and even the most 
solid sugar. The fluid it sends down is probably very liquid ; 
it drives against the sugar, moistens, and dissolves it. The 
* Planche 9, Fig. 10, de Mémoire, “ Sur les parties extérieurs des papillons.” 
