Tibicen pruinosus (Male)
Tuscumbia, Colbert Co., Alabama
coll. M. Reynolds (w/ B. Reynolds & G. Reynolds)


Tibicen winnemana
Garner, Wake County, North Carolina
September 5, 2009
NOTE: Wing Characteristics! The strongly bowed wing trait is a commonly used diagnostic to separate linnei from pruinosus/winnemanna. When looking at wing shape, consider other characters, the bowed wing trait can be seen in other populations/species and is not unique to T. linnei.
05 Sept 2009 (7:00-7:30 pm EDT - collected while making the typical call of the T. pruinosus goup)


Tibicen winnemanna
Male: Lateral view Garner, Wake County, North Carolina, USA
September 14, 2008


Diagnostics such as the "line bisection test" & "wing node position" used to separate T. linnei from T. pruinosus in the Midwest - seems to be challenged when applied to "T. pruinosus/winnemana" (+ other taxa) in parts of the Southeast (& Atlantic Coast). I have noticed that while the point of bisection varies in T. winnemana and T. pruinosus from the upper mid-South, it nearly always bisects the designated wing cell somewhere across the last half or third. This point of bisection is often very near, on the point of coalescence, and in some cases even anterior to the point of coalescence between the C (costal vein) & SC (subcostal) - a characteristic predicted for T. linnei. Midwestern conventions and use of this test suggest little if any bisection of the designated wing cell at all in members of the pruinosus group.

PLEASE REFER to the following reference site: incl. Specimen Key with images (9)
http://insects.ummz.lsa.umich.edu/fauna/Michigan_Cicadas/Michigan/key.html

In support of the test, the point of bisection is "relatively consistent" in most T. linnei and crosses the halfway point nearly everytime either on the point of coalescence (in females) or anterior to the point of coalescence (usu. males).

NOTE: Some variation exists between males and females of T. linnei and among populations of T. linnei. The "line bisection test" is not an ABSOLUTE. Even for T. linnei, there have been populations and isolated specimens which DO NOT conform nor meet the expected test results!

Although this test has some support and validity in the upper Midwest, it is of little use if you wish to separate specimens, particularly females, of T. winnemana, T. pruinosus and T. linnei collected below the Mason-Dixon Line. Using this character and test, as a stand alone deciding factor, may (and often does) result in erroneous identification.

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Costal Margin used in id!
Please refer to the follwing paper for discussion on the idenification of T. linnei and separation of this species from other related species (incl. T. pruinosus & T. canicularis).

http://entnemdept.ufl.edu/walker/buzz/c700lb28.pdf
Refer to page 226 for "wing bend" discussion!

According to Beamer and supported in other manuscripts, the shape of the opercula of the males in T. linnei is the ONLY true deciding factor, not the wing shape. I have had this discussion with several leading cicada specialists and few of them weigh heavily on the costal margin diagnosis any longer for identification of linnei or separation of it from similar related types.

Bowing in the costae and use of the "line bisection test" for species determination can fail. There is significant overlap in this trait and strong bowing in the costae can be seen in any of the following taxa: T. linnei, T. pruinosus, T. winnemana and T. canicularis (to a lesser extent T. robinsonianus). Due to overlap, it is not possible to separate the species based on this character alone!

Moved from Linne's cicada.

T. linnei has a bold black bar (mask) across the face. The mask on T. linne is usually un-interupted. The bar across the face of this cicada is interupted with green along the facial and antennal sutures!

Typical example of T. pruinosus from much of the upper mid-south west of the Appalachians.