HOW ANIMALS EAT. 
59 
the Bee tribe, we have a transi¬ 
tion between the biting and the 
sucking Insects—the mandibles 
“supply the place of trowels, 
spades, pickaxes, saws, scissors, 
and knives,” while the maxillae 
are developed into a sheath to 
enclose the long, slender, hairy 
tongue which laps up the sweets 
of flowers. In the suctorial But¬ 
terfly, the lips, mandibles, and 
palpi are reduced to rudiments, 
while the maxillae are the only 
useful oral organs. These are 
excessively lengthened into a 
proboscis, their edges locking 
by means of minute teeth, so as 
to form a central canal, through 
which the liquid food is pumped 
up into the mouth. Seen un¬ 
der the microscope, the proboscis is made up of innumer¬ 
able rings interlaced with spiral muscular fibres. The 
proboscis of the Fly 
is a modified lower 
lip; that of the Bugs 
and Mosquitos, fitted 
both for piercing and 
suction, is formed by 
the union of four 
bristles, which are 
the mandibles and 
maxillae strangely al¬ 
tered, and encased in 
the labium when not 
Fig. 23.—Proboscis of a Butterfly, magnified. in USe. 
Fig. 22.—Head of a Wild Bee ( An - 
thophora retusa), front view: a, 
compound eyes; b , clypeus; c, 
three simple eyes; d, antennae; e, 
labrum ; /, mandibles; i, maxillae; 
h, maxillary palpi; l, palpi fer; f, 
labial palpi; m, paraglossae; k, 
ligula. 
