58 
INTRODUCTION. 
which forms a canal through which the ailmentary 
juices are absorbed. This instrument, which is some- 
times of great length, is spirally convoluted when 
unemployed, but it can be unrolled with great ra- 
pidity, and is admirably fitted to explore the tubular 
corollas and deep-seated nectaries of flowers, for the 
purpose of extracting their sweet secretions. It is 
of a cartilaginous substance, and owes its great flexi- 
bility to its being composed of numerous rings or 
transverse fibres, bearing some resemblance to the 
annulose structure of earth-worms and some other 
animals. It is formed of two distinct pieces, which 
admit of being separated throughout their whole 
length. Each of these pieces is traversed longitu- 
dinally by a cylindrical tube, and being grooved on 
their inner side, they form when united another ca- 
nal in the centre, of a somewhat square form, and 
wider than either of the two lateral ones. The junc- 
tion of the two parts is so close that the enclosed tube 
is perfectly air-tight ; and this union is effected by- 
means of an infinite number of filets, resembling 
the laminre of a feather, which interlace and adhere 
to each other. Of these three tubes, the central 
one alone serves for the influx of the alimentary 
fluids, the two lateral ones being probably employed 
in transmitting air in aid of respiration, which, how- 
ever, is mainly carried on by means of stigmata or 
lateral pores. The outer extremity of the proboscis 
is frequently beset with many membranous papilla;, 
resembling leaflets, which have been regarded by 
