PROC. ENTOMOL. SOC. WASH. 96(4), 1994, pp. 723-725

THE TRIBAL PLACEMENT OF XENOGENUS (: : )

Carl W. Schaefer

Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269-3043.

Abstract.— Xenogenus Berg, 1883. is returned to the Chorosomatini. It had been re- moved therefrom to the Harmostini, based upon overall similarity. However, cladistic evidence indicates that the genus belongs in Chorosomatini. Xenogenus shares two apo- morphies with members of Chorosomatini, and none with members of Harmostini.

Key Words: Chorosomatini, Harmostini, family-group classification, Xenogenus

When Berg (1883) described Xenogenus. Harmostini. They gave two reasons for do- he placed it in Harmostini. Distant (1893) ing so: All members of Harmostini are New agreed, because Xenogenus, like World, but only Xenogenus (of the six gen- and Aufeius (the two members of Harmos- era in Chorosomatini) is New World. And tini), has incrassate and spined hind femora. Xenogenus resembles Harmostes and Au- Barber (1910) also agreed, writing that Xe- feius in both external and internal structure. nogenus has "the appearance of a long, nar- No details of this resemblance are provided, row Harmostes refleculus [sic]" (p. 37). In and no attempt appears to have been made erecting Harmostini (for Harmostes and Au- to find similarities between Xenogenus and feius), Stai (1873: 97) included as defining other members of Chorosomatini. characters incrassate and spined hind fem- The general similarities between Xeno- ora, and a toothlike extension of the prono- genus and members of the Harmostini are tum's anterolateral angles; Xenogenus lacks probably plesiomorphic within the Rho- the latter feature. palinae, and are shared with several mem- In 1967, Chopra transferred Xenogenus bers of other tribes: the spined and incras- from Harmostini to Chorosomatini. G611- sate hind femora (used by St41 in defining ner-Scheiding accepted this transferral in her Harmostini), small size, lightly setose body, discussion of the genus (1980) and in her translucent forewings sometimes speckled catalog of the Rhopalidae (1983). Chopra and/or suffused with red. These general fea- (1967) moved Xenogenus to Chorosomatini tures—to which both Barber (1910) and largely it, because and the five other genera Brailovsky and Soria ( 1 980) presumably re- he included in that tribe, share uniquely ad- fer—do not uniquely ally the genus and Har- vanced characters of the male genitalia. mostini.

Moreover, the genus lacks the pronotai ex- The fact that Xenogenus is the only New tension, a defining feature of the Harmos- World genus of Chorosomatini does not tini. support Brailovsky and Soria's (1980) con- However, in a paper not mentioned by tention that this genus should be removed

Gollner-Scheiding (1983). Brailovsky and to Harmostini. Although Harmostini is in- Soria (1980) moved Xenogenus back into deed exclusively New World, representa- 724 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Table 1 . Characters whose apomorphic states define Harmostini or Chorosomatini (from Schaefer and Chopra 1982). and their condition in Xcnogentis (apomorphic states are in boldface).

Xi'nogcnivi Chorosomatini

Parameres broad parameres slender" parameres slender Two pairs ventrolateral conjunctival ap- pendages three pairs- three pairs Distal ends of second valvulae fused not fused" not fused Midcephalic sulcus straight sulcus Y-shaped'' sulcus Y-shaped Female's ninth tergum with median apodeme without apodeme' without apodeme Peritreme of metathoracic scent gland appa- ratus absent pentreme reduced" peritreme reduced

" From Chopra (1967). " This paper.

' From G611ner-Scheiding(1978. Table 1).

tives of three other rhopaline tribes also oc- Acknowledgments cur in the New World (Schaefer 1992. 1993). I am grateful to Dr. Luiz A. A. Costa (Rio as members of the other subfamily. Ser- do de Janeiro), who sent me the specimens of inethinae (Gollner-Scheiding 1983). The Xenogenus picturatum Berg upon which this presence of these rhopalines in the New paper is based. World is the result of at least six invasions from the Old World, and the presence of Xenogemis in the New has been explained Literature Cited similarly (Schaefer 1993). Barber, H. 1910. Some Mexican Hemiptera-Het- Moreover, both Ithamar (Hawaii) and G. eroptera new to the fauna of the Linited States. Leptoceraea (Palearctic) (both Choroso- Journal of the New York Entomological Society matini) resemble Harmostini and Xcnoge- 18: 34-.19. mts, particularly in having spined and in- Berg, C. 188.3. .Addenda et amendanda ad Hemiptera crassate hind femora (Chopra 1967). By the .•\rgentina. .Anales de la Sociedad Cientifica Ar- gentina 15: 241-269. "general resemblance" argument they too Brailovsky. H. and F. Soria. 1980. Contribucion al should be placed in Harmostini; and. by the estudio de los Hemiptera-Heteroptera de Mexico: distributional argument, they should be ex- Win Revision de la tribu Harmostini St^l (Rho- cluded from this tribe. The two arguments palidae) y descripcion de una nueva especie. .\na- of Brailovsky and Soria (1980) tend to be lesdel Instilutode Biologia I'niversidad Nacional .\ut6noma Mexico 51 Series Zoologica 1: 123- contradictory. 168. Schaefer and Chopra (1982) analyzed the Chopra, N. P. 1967. The higher classification of the rhopalid tribes cladistically. Those apo- family Rhopalidae (Hemiptera). Transactions of morphies defining Harmostini. and Cho- the Royal Entomological Society of London 1 19: rosomatini. and separating the one from the 363-399. Distant, W. L. 1893. Insecta. Rhynchota. Hemiptera- other, are listed in Table 1. together with

Heteroptera (.Appendix). Volume 1 . In Goodman the states of those characters in Xenogenus. and Salvin, eds.. Biologia Centrali-.Amencana. The genus shares with Chorosomatini both London, x + 462 pp. apomorphies defining that tribe. It possess- Gollner-Scheiding, U. 1978. Revision der Gattung es none of the four apomorphies that define Harmostes Burm., 1935 (Heteroptcra, Rhopali- und einige Bemerkungcn /u den Rhopalinae. Harmostini. dae) Mitteilungen aus dem Zoologischen Museum in I conclude that Xenogenus belongs in Berlin 54: 257-311. Chorosomatini, where placed Chopra (1967) . 1980. Einige Bemerkungen zu den Gattungen il. Fallen, 1814. und Xenogenus Berg, 1883 VOLUME 96. NUMBER 4 725

(Heteroptera, Rhopalidae). Mitteilungen aus dem (Hemiptera: Rhopalidae). Annals of the Ento- Zoologischen Museum in Berlin 56: 111-121. mological Society of America 86: 127-133.

. 1983. General-Kalalogder Familie Rhopali- Schaefer. C. W. and N. P. Chopra. 1982. Cladistic

dae (Heteroptera). Mitteilungen aus dem Zoolo- analysis of the Rhopalidae. with a list of food plants. gischen Museum m Berlin 59: 37-189. Annals of the Entomological Society of America Schaefer, C. W. 1992. The Rhopalinae (Hemiptera: 75: 224-233.

Rhopalidae) and the Palearctic. Proceedings of the StSl, C. 1873. Enumeratio Hemipterorum. Part 3. 4th European Congress of Entomology (Godollo, Kongliga Svenska Vetenskaps-Akademiens Hungary) 2: 652-654. Handlingar. pp. 1-163.

. 1993. Origins of the New World Rhopalinae