INTRODUCTION. 49 
ing them to notice, that which arises from contri- 
buting directly to our interests. 
Hawk-moths and moths possess, of course, many 
properties in common wth butterflies, besides the 
peculiar consistency of the wings. In the confor- 
mation of the mouth, mode of propagation, character 
of the metamorphosis, and many other particulars, 
there is a general agreement, as may be inferred 
from their being associated together in the same 
ordinal division of their class. Instead, therefore, 
of repeating what has been already said respecting 
the various organs, their functions, and several 
other general properties, it will sufiBce to mention 
what peculiarities are observable in the tribes in 
question. Tlieir habits and economy, however, are 
in many cases so remarkable and interesting, that 
in order to do that part of the subject any thing 
like adequate justice, it will require to be treated in 
considerable detail. 
They are distinguished firom butterflies, among 
other characters, by having at the base of the under 
wings, near the anterior edge, a stiff bristle or hair 
which passes through a hook on the under side of the 
anterior wings and maintains them when at rest in 
a horizontal or somewhat inclined position. The 
most characteristic and destinctive mai'k of the 
hawk-moths, the tribe to which we shall first direct 
our attention, is to be found in the form of the 
antennae, which increase in diameter fr-om a slender 
base nearly to the apex, forming a prismatic, fusi- 
form club, and usually terminating in a subulated 
D 
