PROC. ENTOMOL. SOC. WASH. 108(3), 2006, pp. 611 618 REVIEW OF THE NEOTROPICAL LEAFHOPPER GENUS CHLOROGONALIA (HEMIPTERA: CICADELLIDAE: CICADELLINAE), WITH NOTES ON THE GENUS CALDWELLIOLA Stuart H. McKamey Systematic Entomology Laboratory, PSI, Agricultural Research Service, U.S. Department of Agriculture, c/o National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, MRC 168, Washington, DC 20013-7012, U.S.A. (e-mail:
[email protected]) Abstract. — Chlorogonalia Young, 1977, and Caldwelliola Young, 1977, are superficially very similar genera that may not be closely related genera within the tribe Cicadellini (Hemiptera: Cicadellidae: Cicadellinae). Two species, Chlorogonalia ultima Young and Caldwelliola reservata (Fowler), are particularly similar phenotypically and are sympatric in Ecuador (new country record for C reservata). New diagnostic features are given for both genera; two of these features can be assessed in undissected specimens. Caldwelliola tharma (Young) is proposed as a new combination (from Chlorogonalia). Species of both genera are possible vectors of the bacterium Xylella fastidiosa in coffee; Caldwelliola caucana has been directly implicated as a vector of the crespera disease in Colombia. An illustrated key is included to distinguish the four known species of Chlorogonalia. Key Words: Cicadellidae, Xylella fastidiosa, vector, crespera, coffee There are 328 genera and over 2,200 species of sharpshooters (Hemiptera: Cicadellidae: Cicadellinae) in the New World (Leafhoppers of the World Data-base; McKamey, in preparation). The group is unusual in the Cicadellidae for feeding on the host plant's xylem rather than phloem or parenchyma. The xylem is deficient in nutrients and is therefore imbibed and excreted in large amounts, the latter activity giving these insects the common name of sharpshooters. Some members of this group are also well known for vectoring the bacterium Xy-lella fastidiosa. For example, species of the genus Homalodisca Stal vector X. fastidiosa in grape in the United States, causing Pierce's Disease, and genera such as Acrogonia Stal vector it in citrus in Brazil, causing citrus variegated chloro-sis. Most New World sharpshooters were included in two revisions by Young (1968, 1977), the earlier revision covering the tribe Proconiini and the more recent dealing with Cicadellini. Two of the 163 New World genera of Cicadellini, Chlor-ogonalia and Caldwelliola, are extremely similar in both external and internal features but may not even be closely related, their similarities being superfi-cial. In the process of identifying a puta-tive pest species, it was discovered that some specimens (USNM) of Caldwelliola had been misidentified by Young as Chlorogonalia, indicating that a clearer diagnosis of the two genera was needed. No host records have been reported in the literature for either, but both genera
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