Interactive keys to the genera and higher taxa of treehoppers (Hemiptera: Membracidae) of the United States: Part 1. Primer.

By Matthew S. Wallace, 15 Sept 2010.
Departmental of Biological Sciences, East Stroudsburg University, 200 Prospect St., East Stroudsburg, PA 18301. Email:

Suggested citation

 Wallace, M. S. 2010 (and updates). Interactive keys to the genera and higher taxa of treehoppers (Hemiptera: Membracidae) of the United States. Parts 1-3. In Deitz, L. L., and M. S. Wallace (team leaders). Treehoppers: Aetalionidae, Melizoderidae, and Membracidae (Hemiptera). []

This three-part work presents a primer (Part 1, which follows below) and illustrated multi-access keys to the treehoppers of the United States, including a key to the genera (Part 2) and a key to the subfamilies and tribes (Part 3).

Key to genera (Part 2) includes 68 treehopper genera, 64 of which are reported from the United States. The genera Atymnina, Godingia, Hemicardiacus, and Smilirhexia, all Neotropical in distribution, were added to provide a comprehensive key to the genera of the tribe Smiliini. The key generally treats only the continental U.S.--no treehoppers are reported from Alaska, and two of the three genera found in Hawaii (Spissistilus, Vanduzea) are included in the key. The genus Tricentrus, however (reported from Hawaii), is not included. Eighty morphological characters and one geographic character are used to identify these taxa. For the geographic character, taxa were coded based on their occurrence in three regions of the country as follows: Central and Eastern U.S.; Southwestern U.S. (AZ, CA, CO, NM, NV, TX, UT); and Northwestern U.S. (ID, MT, ND, OR, WA, WY).

Key to subfamilies and tribes (Part 3) is an illustrated multi-access key to the five subfamilies and fourteen tribes of the treehoppers of the United States. It essentially treats only the continental U.S. (see note above). Forty-one characters are used to identify the taxa.

Unlike traditional dichotomous keys, interactive keys allow users to choose morphological characters and their associated states from any body region. To identify a specimen, character states are selected that most closely match the specimen in question. Taxa without that state are eliminated from the key, leaving only taxa that possess the chosen features. Further character states are chosen until one taxon (or a few taxa) remain.

  1. Select a region of the body (e.g. head, wings, legs, genitalia) by scrolling down the page. Users unfamiliar with treehopper anatomy may wish to study the illustrations on the next page. After choosing a character, click on a character state that matches the specimen. Character states displayed in brighter shades of green will eliminate the most taxa from the key (alternatively, users may also click “add” displayed above the figures to choose character states). Following a selection, taxa that possess this character state will be displayed at the top of the page in the “OTUs remaining” row (OTUs=Operational Taxonomic Units). Some taxa may possess more than one character state--there is often significant morphological diversity among members of large genera.
  2. Below most characters are associated figures that assist in selecting which character state best matches the specimen in hand. Click on a figure to see an enlarged view.
  3. a. To ‘undo’ a single character state choice, select ‘chosen states’ in the main toolbar. Then, from the list of character states presented, click on ‘remove’ to undo the appropriate choice. To return to the key, select ‘main’.
    b. If you wish to simply start over (or undo all character state choices), click on ‘reset key’ at the upper right corner. In the “OTUs eliminated” row, select “R”, and this will return the entire set of states associated with that taxon (and possibly other taxa) to the key.
  4. For the generic key only: If only a few taxa remain, habitus taxon photographs may help to distinguish among them. To view this content, simply click on a taxon name.
  5. Note that after selecting a character state, the parent character may remain in the key due to the possibility that remaining taxa may possess the remaining character states. The remaining inapplicable character states will be italicized and users will not be able to select them.
  6. With certain groups (especially the tribe Ceresini) accurate identification to genus may require the dissection of the male genitalia. These male features are thus necessarily included in the keys, however, the dissection of males and females involves techniques (Deitz 1975, Wallace and Deitz 2004) that non-specialists may find prohibitively challenging. In such instances, the multi-access keys should at least greatly limit the number of possible choices.



  1. To narrow down the list of “possible taxa” quickly, it is suggested that users start with pronotal characters, and then proceed to wing and leg characters. For most characters, figures illustrating various states are given below the list of character states.
  2. Keys were based on U.S. taxa only. Consequently, they may not be useful when attempting to identify foreign specimens (e.g. tropical) to genus, subfamily, or tribe. If only a few taxa remain, habitus taxon photographs may help to distinguish among them. To view this content, simply click on a taxon name.
  3. If data were unknown or missing at the time of coding, all possible character states were coded in mx to avoid eliminating the taxon as a possible positive identification. Thus, for some characters, such as “live color” and certain genitalic characters for particular taxa, the list “OTUs remaining” will be abnormally large. In this situation, it is suggested that users choose additional supplemental characters to narrow the possibilities.
  4. Concerning the geographic distribution character, if a taxon was questionable for a region, it was coded as present for that region. Thus it is wise to employ a number of morphological characters in combination with distribution to confirm or rule out any taxa that may be problematic in a region.
  5. Do not use the “back” and “forward” keys on your Internet browser toolbar. This will “crash” the key.

Characters in the key were derived from a combination of a comparative examination of treehopper specimens and from previously published data in morphological descriptions, keys, illustrations, and matrices in various treehopper works, but especially from: Goding (1892; Ball 1931), Deitz (1975), Kopp and Yonke (1973a-c, 1974, 1979), Dietrich and Deitz (1991), Dietrich et al. (2001), Cryan et al. (2004), Wallace and Deitz (2004), and Godoy et al. (2006). Geographic regions were coded from various sources listing treehopper distributions, but especially Metcalf and Wade (1965) and McKamey (1998). Numerous illustrations from Deitz (1975) and Kopp and Yonke (1979) were scanned and used as figures in the key (see Acknowledgments). Permission from the author was given to present figures from Deitz (1975) and from the Entomological Society of America to present figures from Kopp and Yonke (1979). Taxa were scored in a morphological data matrix created in Microsoft® Excel. The matrix was then uploaded into mx® software (Yoder et al. 2006) where the interactive key was created. Many figure images and taxon images in the key were taken with a Nikon® digital camera/dissecting microscope using Nikon Elements® software.

This research was funded by a 2009-2010 East Stroudsburg University Presidential Research Fund award and a 2009-2010 State of Pennsylvania State System of Higher Education Faculty Professional Development Grant. I am grateful to my colleagues Andrew R. Deans, Matthew J. Yoder, and Katja C. Seltmann (NCSU Insect Museum, North Carolina State University) for assistance in the construction of the keys. James R. Baker, Robert L. Blinn, Lewis L. Deitz, Stuart H. McKamey, Istvan Miko, Mark J. Rothschild, and P. Sterling Southern provided peer reviews with many useful comments on the keys and primer. I also thank the Entomological Society of America for permission to reproduce figures from Kopp and Yonke (1979) and the College of Agriculture and Life Sciences, North Carolina State University, and the North Carolina Agricultural Research Service for permission to reproduce figures from Deitz (1975).

Literature Cited

Ball, E. D. 1931. A monographic revision of the treehoppers of the tribe Telamonini of North America. Entomologica Americana 12: 1-69.

Cryan, J. R., J. A. Robertson, and L. L. Deitz. [2004 (dated 2003)]. The New World Treehopper Tribe Microcentrini (Hemiptera: Membracidae: Stegaspidinae): Monographic Revision and Phylogenetic Position. Entomological Society of America (Thomas Say Publications in Entomology: Monographs), Lanham, Maryland. 114 pp.

Deitz, L.L. 1975. Classification of the higher categories of the New World treehoppers (Homoptera: Membracidae). North Carolina Agricultural Experiment Station Technical Bulletin 225: 1–177.

Dietrich, C. H., and L. L. Deitz. 1991. Revision of the Neotropical treehopper tribe Aconophorini (Homoptera: Membracidae). N.C. Agric. Research Service Technical Bulletin 293: 1-134.

Dietrich, C. H., S. H. McKamey, and L. L. Deitz. 2001. Morphology-based phylogeny of the treehopper family Membracidae (Hemiptera: Cicadomorpha: Membracoidea). Systematic Entomology 26: 213-239.

Goding, F. W. 1892. A synopsis of the subfamilies and genera of the Membracidae of North America. Transactions of the American Entomological Society 19: 253–260.

Godoy, C. C., X. M. Garnier, and K. Nishida. 2006. Treehoppers of tropical America. Instituto Nacional de Biodiversidad, Santo Domingo de Heredia, Costa Rica. 356 pp.

Kopp, D. D., and T. R. Yonke. 1973a. The treehoppers of Missouri: Part 1. Subfamilies Centrotinae, Hoplophorioninae, and Membracinae (Homoptera: Membracidae). Journal of the Kansas Entomological Society 46: 42 64.

Kopp, D. D., and T. R. Yonke. 1973b. The treehoppers of Missouri: Part 2. Subfamily Smiliinae; tribes Acutalini, Ceresini, and Polyglyptini (Homoptera: Membracidae). Journal of the Kansas Entomological Society 46: 233 276.

Kopp, D. D., and T. R. Yonke. 1973c. The treehoppers of Missouri: Part 3. Subfamily Smiliinae; tribe Smiliini. Journal of the Kansas Entomological Society 46: 375 421.

Kopp, D. D., and T. R. Yonke. 1974. The treehoppers of Missouri: Part 4. Subfamily Smiliinae; tribe Telamonini (Homoptera: Membracidae). Journal of the Kansas Entomological Society 47: 80 130.

Kopp, D. D., and T. R. Yonke. 1979. A taxonomic review of the tribe Ceresini (Homoptera: Membracidae). Entomology Society of America Miscellaneous Publications 11(2): 1-97.

McKamey, S. H. 1998. Taxonomic Catalogue of the Membracoidea (exclusive of leafhoppers): Second Supplement to Fascicle 1 -- Membracidae of the General Catalogue of the Hemiptera. Memoirs of the American Entomological Institute 60: [1] 377.

Metcalf, Z. P., and V. Wade. 1965. General Catalogue of the Homoptera. A Supplement to Fascicle I Membracidae of the General Catalogue of Hemiptera. Membracoidea. In Two Sections. North Carolina State Univ., Raleigh. 1552 pp.

Wallace, M. S., and L. L. Deitz. 2004. Phylogeny and systematics of the treehopper subfamily Centrotinae (Hemiptera: Membracidae). Memoirs on Entomology International 19: [i]-iv, 1-377.

Yoder, M. J., K. Dole, K. C. Seltmann, and A. R. Deans. 2006 (to present). Mx, a collaborative web based content management for biological systematists. [LINK]