27 mm body length (guide photo)
Body Length: (30-35 mm)
Body Length (~1.0-1.25 inches - max 1.4)
Total length incl. wings (~2.0 to 2.25 inches)
Canadian examples seem a bit smaller by comparison to those specimens collected in the US (appears closer to canicularis in size)
(Larger sample sizes collected from across the range are needed to more accurately address these observations)
As originally described, most similar to linnei (and pruinosus)
Physical traits based on specimens collected in the US (some collected while singing or responding to calls - positive id's).
1) complete black face mask
2) ventral black abdominal stripe (often better delineated than in linnei)
3) Usu. no bow to costae (Rare examples may exist)
4) males have short oblique tan opercula
5) females usu. possess paired white spots at the base of the abdomen (> seen in fem. of linnei but < seen in fem. of pruinosus)
6) there is usu. a thin black hair-line mark that bisects the pronotal collar (not observed in winnemanna or pruinosus populations across the southeast / rare in linnei / may be present in some northern pruinosus - observed in some suspected hybrids)
Widespread across the Southeast (Mid-South & Upper South)
Scattered reports from the Mid-West
Scattered reports from s. Canada
NOTE: Canadian examples do not seem consistent in habitat preference (plant communities) or morphological characters seen in populations or specimens collected from the Southeastern and lower Mid-Western US.
Dr. Hamilton reports Canadian examples of "robinsonianus" appear to be hybrids between T. canicularis and T. linnei; however, populations represented across the US far to the south seem distinct. It is not unlikely that T. linnei and T. canicularis hybridize to the north and these hybrids may possess overlapping characters with T. robinsonianus to the south (?) - as several Tibicen species possess overlapping traits often confounding id.
NOTE: To date, the consensus is that T. robinsonianus (as originally described) is a distinct taxon with a southern and central US distribution and not of hybrid origin (per. comm.).
Sanborn reports n. FL (?)
No additional info on Florida records is available (per. comm.)
Common in the higher grounds = "Hill Country"
(incl. the Fall-line hills, Cumberland Plateau, Piedmont Plateau, upper and mid-Mississippi River Valley, and scattered across Appalachia - possibly occurs in the lower elevations on the fringes of the upper Coastal Plain)
Widspread and most common in the following states:
n. LA, AR, OK, MO, KY, TN, MS, AL, GA, SC, NC, & VA
Also found in parts of the lower Midwest incl. the south & central parts of IL, IN and OH
Reported from e. TX(?), WV(?) and MD(?) ... likley found in a few northern states immediately adj. to VA
NOT verified to occur in the northeastern US, upper mid-Atlantic & New England, or the Great Lakes region of the US (per. comm.).
Cicadas with "similar morphologies" have been collected and reported far to the north (New England & Great Lakes), but these specimens seem most congruent with T. canicularis and suspected to belong to that taxon. Audal records for T. robinsonianus have not been verified north of the Southeastern/Mid-Atlantic states in the eastern US or from the extreme upper mid-West/adj. Great Lakes region of the US (per. comm. & reports).
Canadian group seems dominant in deciduous forests with mixed conifers.
Late summer (July-early Sept ?)
Although Bill Reynolds (pers. obs. & per. comm.)
, finds that US records for robinsonianus are limited to the South, Mississippi basin and the lower Midwest (seemingly not as abundant and/or absent northward), Dr. Hamilton has found that they do occur in s. Canada. Perhaps they are representative of a relict or isolated member of the complex and we should place them in this subgroup. Based on limited observation and material, populations belonging to the "robinsonianus complex" in Canada may not completely adhere to the features used diagnostically to those in the southern & central US! Until specimens can be compared from across the range, we should acknowledge this material until more is known.
Perhaps contributors can take more images and the info will help build a better picture of what's going on.
Most similar to linnei, pruinosus, winnemanna, and canicularis
There has been some speculation that T. robinsonianus may be a hybrid between linnei and canicularis, however, given the geographic ranges of the three, this hypothesis seems unlikely across much of the robinsonianus range.
Despite the original description comparing this cicada to T. linnei, there is some thought, T. robinsonianus may actually be more closely allied to the "pruinosus complex" than to any other members of the "Green Tibicen" group (?).
"Green Tibicen Species"
Collectively, yet informally, referred to as the "Green Tibicen species" (per. comm.), the following cicadas are often difficult to differentiate and all appear to be very closely related. Genitalic analysis of the males suggest these species are very closely related and morphological differences between and among the species are slight. It is also thought (based on observations) that several of these may be involved in complex hybrid zones; however, more work is needed to substantiate and better understand these observations.
Tibicen pruinosus pruinosus var. fulvus Beamer 1924 [syn. T. pruinosa var. fulva], "Pale Scissor(s) Grinder Cicada"
"Southern Dog-day Cicadas"
Loosely & informally referred to as the "Southern Dog-day Cicadas" ("coined", Bill Reynolds
), the following taxa are mostly "southern" in distribution and appear to be closely related. These cicadas share several traits, incl. elongated opercula in the males, rapid trill and/or clicking calls, and unusually wide heads relative to body dimension (head widths usu. exceed thoracic widths).
(*appears to be the most divergent member within this group - ??)