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A Key to the superfamilies of the Lepidoptera
with special reference to North and South Dakota
About keys
Use of a key is the time honored method to identify
an unknown organism when
direct comparison with
previously determined specimens is not possible.
Keys
are more reliable than simple picture matching for the
reason that in a
comparison between your specimen (or photograph) and a textbook photograph, a
suite of identification characters rather than overall
similarity is emphasized.
Formerly,
and ironically, the stumbling block to the use of
keys by
non-specialists has
been mastering the terminology which
in the past was clarified by the use
of pen
and ink illustrations. Now, with the easy facility of digital imagery,
terminology is clarified by the use of photographs. Part of the digital
imaging revolution that touches the realm of identification is that even an
average digital picture may be easily enlarged or enhanced so that, given direction as
to what to look for, 'key' characters can often be discerned.
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Using a key is like playing a game of 'twenty questions' or reading a good
detective story. By answering crucial questions or analyzing critical clues, a
conclusion is reached as to the identity of an object, a suspect, or in this
case, the identification of a particular specimen to species. Sets of
questions employed in keys are termed couplets. Keys on this web
site are (as of this writing) of two types, either dichotomous couplets (two
questions in apposition) or in the case of very large keys, quadrichchotomous
sets of (4) questions, each question focusing on a particular character. A
short dichotomous key to identify a Cecropia moth, Hyalophora cecropia
(the large moth on the homepage of this web site) might run as follows:
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| 1. Forewings and
hindwings similar in shape and venation (primitive moths). |
| 1.' Forewings and hindwings
of dissimilar shape and venation (most higher Lepidoptera. Go to 2 |
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| 2. Hindwings with scale
fringe along outer margin at least 1/3 as wide as the wing (micro-moths) |
| 2.' Hindwings with fringe
very narrow or absent (macro-lepidoptera) Go to 3 |
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| 3. Wings coordinated by
a frenulum-retinaculum coupling mechanism (most macro-moths). |
| 3.' Wings coordinated by an
underlapping expanded humeral lobe of the hindwing (a few groups of
macro-moths and butterflies) Go to 4. |
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| 4. Antennae capitate
(clubbed) (butteflies). |
| 4.' Antennae not capitate (a
few groups of macro- moths). Go to 5. |
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| 5. Forewing venation
quadrifid (Lappet moths). |
| 5.' Forewing venation trifid
(Mimallonids, Silk moths, Giant silk moths) Go to 6. |
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| 6. Antennae of males
simple, cilliate, or bipectinate (Mimallonids, Silk moths Giant Silk moths
subfamily Hemileucinae). |
| 6.' Antennae quadripectinate
(Family of Giant silk moths, Saturniidae subfamilies Ceratocampinae,
Saturniinae). Go to 7. |
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| 7. Antennae of males
with apical 1/3 ciliate, of females ciliate (Royal moths, subfamily
Ceratocampidae). |
| 7.' Antennae of both sexes
quadripectinate (true giant silk moths, subfamily Saturniinae). Go to
8. |
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| 8. Discal cells of both
wings closed (Early giant silk moths, tribe Saturniiini). |
| 8.' Discal cells of both
wings opened (Derived giant silk moths, tribe Attaciini). Go to 9. |
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| 9. Dorsal abdomen with
segmental spots or unicolored (genera: Samia, Rothschildia, Eupackardia
and Callosamia), |
| 9.' Dorsal abdomen having
each segment with a pale posterior marginal band (Genus Hyalophora).
Go to 10.
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| 10. Wings with post median line
white or black and white (H. columbia, H. euryalus, and H. gloveri). |
| 10.' Wings with post median line black,
white and red. Hyalophora cecropia. Cecropia moth. |
The above key was tailored specifically to unambiguously
identify Hyalophora cecropia with the fewest number of couplets. A
somewhat longer key is required to key out far more species with the greatest
efficiency. Note that structural rather than color characters were used in
all but the last two couplets and that even in this short key, specialized
terminology was necessary. In the Superfamily/family key that follows,
images will clarify terminology.
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