The order Coleoptera probably contains the largest
number of described species of any insect order.
Beetles are found in almost every habitat, and range
in size from 1 – 100mm. in length. The heaviest
known insect is a scarab beetle.
The diversity of this order contributes to the complexity
of writing classification keys that encompass
all exceptions. Frequently generic keys that are written
to cover all species become so complex and
lengthy that even experts get bogged down in details.
In order to introduce you to this order without
adding to the difficulty of identification I have constucted
a key to 50+ families of beetles that you
should be able to identify (Florida). Keep in mind
that there are more than 100 families of beetles, and
that this key is only intended to introduce you to the
terminology and morphology that you will use in other,
more comprehensive keys.
The keys that follow are dichotomous, meaning
that each couplet has 2 paragraphs of characters
from which you are to pick the best match. Through
process of elimination you should be able to work
your way through this key to a reasonable identification
choice. If you find that every couplet seems to
be a difficult choice, you have likely made a mistake
or the specimen you are trying to identify belongs in
a family not included in the key. When you arrive at
a tentative identification, look at examples of the
family to see if you have a specimen that fits members
of that family. Realize that some of the larger
families have many different morpho-types, so be
cautious here!
Terminology: Beetle identification requires you
to become familiar with antennal shapes, tarsi (formulas,
shapes of segments) mouthparts (labial and
maxillary palpi), ventral characters (sterna, pleura,
coxae), and other morphological characters. Size
and color of specimens will not usually help you identify
beetle families unless you are already familiar
with the morphological characters that identify each
family. Therefore, do not try to remember families
from pictures or by size and color. There is too much
variation. Learn the morphology that sets each family
apart. Family names have undergone numerous
changes with the publication of American Beetles
(Arnett and Thomas,2001) vols. 1 and 2. I follow traditional
family names here