Identification
The Northern and Western populations/"race" ("ssp. pronotalis") can best be characterized as follows:
1) "Polymorphic" in color and pattern
2) The pronotum can be variable in color ranging from bright green, to yellow, orange, tan and may or may NOT have extensive patterns or trace patterns centrally. TAXONOMIC dilemma! ... Individuals with patterns on the pronotum are often referred to as form "pronotalis". In contrast, individuals of this race lacking pronotal patterns are usually called form "walkeri" (not to be confused with populations called "ssp. walkeri").
3) The mesonotum is subject to variable color patterns and schemes as described for the pronotum.
4) The abdomen is usually black with dark or reddish brown evident in some individuals.
5) NOTE: The described subspecies, "pronotalis" and "walkeri," are often debated. Most agree the populations of this species better represent a cline (the clinal relationships still need more work); however, based on ambiguities as to which variety is which, I have separated and listed both "population groupings (i.e ssp.)" under "No Taxon" headings here on BG.
6) Pay close attention to the populations often "referred to as the nominate subspecies pronotalis" and the names often used or applied to individuals based on the "mesonotal pattern" or "forms" (i.e. var. pronotalis & var. walkeri). The taxon "T. pronotalis pronotalis form walkeri" and T. pronotalis ssp. walkeri are not generally considered to be the same but often confuse the nomenclature.
T. pronotalis is one of our LOUDEST CALLING EASTERN Tibicen SPECIES.
However, it's not the males' calls that are so ear splitting, but rather the alarm squawks they produce when threatened or picked up! The alarm squawk of a male Tibicen pronotalis (syn. walkeri Metcalf), produces a mean sound pressure level of 105.9 dB(50cm) making it among the loudest insects in the world!
Refer to this link for details
Loudest Insects
GENERAL DESCRIPTION: Tibicen pronotalis (syn. walkeri)
1) SIZE: One of our largest eastern species often rivaling T. auletes and T. resonans in size.
[Avg. 2.2-2.7 inches in total length - incl. wings....some specimens may be slightly larger, especially those from the southern part of the range]
2) BODY COLORATION: several color forms can be encountered across the range (referencing "ground coloration")
"Lime-Green": can be widespread - but often more typical of Eastern & Southeastern Populations. Populations in Alabama, Georgia and n. Florida are typically bright lime green with patternless pronota and bright lateral fulvous patches on the mesonota.
"Light Olive/Taupe": widespread but often more common in the western & southwestern reaches of the range - west of the Miss. R.
"Greenish Ochreous-Tan": widespread but often more common in the west central Gulf States (LA & e. TX), western & southwestern reaches of the range - west of the Miss. R.
"Ochreous" or "Yellow-Orange": Seems to occur in the more northern populations, especially those adj. to the Miss. R. and along the periphery of the Plains and Grassland fragments west into the eastern Tall-Grass Prairies ... replaced by dealbatus in the western Prairies
EYE COLORATION: "Light" usu. with a bluish, bluish-grey or purplish cast (rarely the grey-tan or sandy color seen in resh or auletes)
3) PATTERN: The pattern of the mesonotum is relatively consistent in "pronotalis" but may vary some in color and amounts of black (esp. in northern specimens). The lateral fulvous areas are often bright red or brick-colored (occasionally with heavy black). The pronotum may be solid and patternless (typical of southeastern populations) or may exhibit varying degrees of pattern centrally - often intricate (in some extremes, this pattern may be represented by a large centralized black blotch, much as seen in examples of T. cultriformis).
4) VENTER: Lightly Pruinose (usually ochreous with hints of pale green) / No dark pigmentation
5) The dorsum of the abdomen can be described as blackish. In most specimens reviewed, the dorsal aspect of the abdomen is characterized with some slight rust coloration visible on half or more of the dorsal segments.
6) The heavily infuscated (i.e. smoky black-grey) "Z" visible towards the ends of the forewings and typical of most Tibicen species is usually poorly developed to absent in this species with only the cross veins being evident (i.e. The radial and radiomedial cross veins of tegmina, forewing, NOT heavily infuscated or darkened.).
7) The costal margins of the forewings - heavy veins of the leading wing edge - are usually bowed or noticeably arciform (more so than seen in several similar species).
8) MALES: opercula are oblique/rounded & ochreous to olive-yellow colored (rarely orangish-tan)
9) CALL: The call has been described as a deep rhythmic "Yeee-Yeee-Yeee-....." with a subtle underlying rumble ..."broom-broom-broom-...." (difficult to vocally immulate or "spell out"). This species calls from late afternoon 'til well after sunset. The calls of the males are often heard as late as 10 to 11 PM (EDT & CDT).
10) "SUBSPECIES": There are two poorly defined "subspecies". These ssp. or forms are perhaps better described as clinal variants with overlapping coloration & varying degrees of pattern.
Tibicen pronotalis pronotalis (North & West) & Tibicen pronotalis walkeri (South and East)
NOTE: Although some of these variants exhibit phenotypic tendencies with strong geographic affiliations (i.e.
clinal), they are not likely representative of "subspecies".
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Distinquishing traits of T. dealbatus are as follows:
1) ABDOMEN: T. dealbatus exhibits greater pruinosity (white powdered wax) than seen in pronotalis. The pruinosity is usually arranged in "dotted stripes" along the sides of the abdomen and dorsal abdominal midline (rare in pronotalis).
2) THORAX: T. dealbatus exhibits greater pruinosity on the thorax (esp. the mesonotum)
Often similar in appearance and confused with "The dorsatus Group"
3) T. dealbatus is usually a bit more compact and has a slightly narrower head than seen in pronotalis
4) COLORATION: Variable in both taxa and not entirely diagnostic!, - tendencies - when T. dealbatus is green, it is typically a duller "pea green" (often more of a ~lime green in pronotalis) - when tan, it is typically more of a sandy-brownish tan as opposed to a ochreous yellow or taupe (green-tan) seen in pronotalis.
5) DISTRIBUTION: Geographic distribution of pronotalis and dealbatus and how they may relate.
To date, neither pronotalis nor dealbatus seem to be sympatric in their "pure" form. Although there is evidence to suggest genetic exchange and blending among adjacent populations (pronotalis x dealbatus), it is unlikely to find both taxa in their "pure forms" coexisting side by side.
6) CALL: The call of dealbatus is identical to that of pronotalis and may be described as a deep rhythmic "Yeee-Yeee-Yeee-....." with a subtle underlying rumble ..."broom-broom-broom-...." (difficult to vocally immulate or "spell out"). This species calls from late afternoon 'til well after sunset. The calls of the males are often heard as late as 10 to 11 PM EDT.
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T. resh vs. T. pronotalis
differentiating Tibicen resh from the "T. pronotalis Group"
The "Z" infuscation found near the tip of the forewing is prevalent in resh and NOT so in pronotalis & dealbatus (usu. very faded or absent).
Note the evident "Z" towards the tips of the forewings
(NOTE the faded "Z" - the cross veins are evident but not heavily blackened)
Tibicen pronotalis var. pronotalis
(NOTE the faded "Z" - the cross veins are evident but not heavily blackened)
Tibicen pronotalis var. walkeri
(NOTE the lack of a smoky black "Z" - ONLY the cross veins are evident)
Tibicen pronotalis var. pronotalis
(NOTE the lack of a smoky black "Z" - ONLY the cross veins are evident)
Range
var. pronotalis ("ssp. pronotalis"??)
Central USA
Mid-Western States adj. to the Mississippi River west in the eastern Plains (this taxon is replaced by T. dealbatus in the central Plains and ssp. walkeri to the south and east).
Populations best fitting the description for ssp. pronotalis can be found in states along the eastern banks of the Mississippi River, upper mid-South and western Gulf States, where the populations become increasingly suggestive of the described "ssp. walkeri" as one travels east.
Tibicen pronotalis
West of the Appalachians incl. Mid-South, Lower Mid-West and eastern Plains States
e. Texas, e. Oklahoma, Louisiana, Arkansas, Missouri, e. Kansas, e. Nebraska, Iowa, South Dakota, North Dakota, Illinois, Indiana(?), w. Kentucky, w. Tennessee, Mississippi, Alabama, sw. Georgia and extreme n. Florida (nr. the tri-states - GA, FL, & AL jnc.)
Remarks
1) Songs of pronotalis and dealbatus are identical.
2) Appears to cross with dealbatus - with which it may be conspecific (?).
3) Both pronotalis and dealbatus will call well after sunset (during the day upto ~10:00pm or later), an unusual behavior for most US cicada species.
4) There are several color forms ranging from bright green to dull straw-yellow + intermediates.
5) There are two poorly defined "subspecies". These ssp. or forms are perhaps better described as clinal variants with overlapping coloration & varying degrees of pattern.
Tibicen pronotalis pronotalis (North & West) & Tibicen pronotalis walkeri (South and East)
NOTE: The observed differences appear to represent "individual variation". Although some of these variants exhibit phenotypic tendencies with strong geographic affiliations (i.e.
clinal), they are not likely representative of "subspecies".