4 RE A NATURAL HISTORY OF WASPS. 
mouth of insects and Mammalia. The figure of 
speech may be very convenient, but the analogy is 
very fanciful, which finds our upper and lower lips 
severally reproduced in parts so dissimilar from each 
other as the horny labrum and the complex labium, 
or compares our upper and lower jaws respectively 
to the horny mandibles and the complex maxille. 
They may answer similar purposes, but the things 
themselves are wholly different. 
But if we limit the range of our fancy within more 
legitimate boundaries, and content ourselves with 
tracing the real analogy which exists between the 
component parts of the mouth in different families of 
insects respectively, we shall still find enough to do. 
Dissimilar as the various parts of the mouths of dif- 
ferent insects may appear at first sight, both in form 
and function, nevertheless, their essential identity 
has been traced in the most satisfactory manner. 
To take a few familiar instances. In some of the 
Eumenide the mandibles cross each other, or stretch 
out into a beak, thus forming a pair of forceps 
adapted to hold anything. In the Vespx they are 
shortened into a saw fitted with a limb for flattening 
the paper. In the male stag-beetle they appear as 
horns of as full proportions as those of the quadruped 
from whence they are named. In the flea these are 
the cutting lancets which make holes in our skins, 
and in the butterfly they are almost obsolete. 
Or take the maxille. In the flea these are trans- 
formed, like the mandibles, into lancets. But in 
the butterfly and moth they undergo quite another 
change of form. They are extended to the length of 
one or two, or more inches, while the edges are turned 
