BREDIN-ARCHBOLD-SMITHSONIAN BIOLOGICAL SURVEY OF DOMINICA The Family Dolichopodidae with Some Related Antillean and Panamanian Species (Diptera) HAROLD ROBINSON SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 185 SERIAL PUBLICATIONS OF THE SMITHSONIAN INSTITUTION The emphasis upon publications as a means of diffusing knowledge was expressed by the first Secretary of the Smithsonian Institution. In his formal plan for the Insti- tution, Joseph Henry articulated a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This keynote of basic research has been adhered to over the years in the issuance of thousands of titles in serial publications under the Smithsonian imprint, com- mencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: Smithsonian Annals of Flight Smithsonian Contributions to Anthropology Smithsonian Contributions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Studies in History and Technology In these series, the Institution publishes original articles and monographs dealing with the research and collections of its several museums and offices and of professional colleagues at other institutions of learning. These papers report newly acquired facts, synoptic interpretations of data, or original theory in specialized fields. These pub- lications are distributed by mailing lists to libraries, laboratories, and other interested institutions and specialists throughout the world. Individual copies may be obtained from the Smithsonian Institution Press as long as stocks are available. S. DILLON RIPLEY Secretary Smithsonian Institution SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 185 BREDIN-ARCHBOLD-SMITHSONIAN BIOLOGICAL SURVEY OF DOMINICA The Family Dolichopodidae with Some Related Antillean and Panamanian Species (Diptera) Harold Robinson SMITHSONIAN INSTITUTION PRESS City of Washington 1975 ABSTRACT Robinson, Harold. Bredin-Archbold-Smithsonian Biological Survey of Dominica: The Family Dolichopodidae with Some Related Antillean and Panamanian Species (Diptera). Smithsonian Contributions to Zoology, number 185, 141 pages, 231 figures, 1975.—The Dolichopodidae of the Island of Dominica are surveyed and keys and descriptions are presented for the 30 genera and 113 species. Three genera, Cryptopygiella, Dominicomyia, and Micromedetera, and 69 species from the island are described as new. New species described from other localities include Asyndetus deficiens from Mona Island, A. pogonops from Puerto Rico, Enlinia jamaicensis, E. crassipes, E. farri, Harmstonia acuta, H. jamaicensis, and Micromedetera wirthi from Jamaica, and Cymatopus wirthi, Enlinia crassitibia, E. wirthi, E. panamensis, Harmstonia wirthi, H. panamensis, and Micromedetera shannoni from Panama. Two groups of genera, Enlinia-Harmstonia and Micro- medetera, are noted for their particularly small size and elusive habit. It is sug- gested that these microdolichopods have a different basic biology, perhaps partially abandoning the predaceous habit that is characteristic of most of the family. Special note is taken of members of the predaceous genus Medetera found in proximity to various termite nests on Dominica. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SI PRESS NUMBER 5166. SERIES COVER DESIGN: The coral Montastrea cavernosa (Linnaeus). Library of Congress Cataloging in Publication Data. Robinson, Harold Ernest, 1932- Bredin-Archbold-Smithsonian biological survey of Dominica. (Smithsonian contributions to zoology, no. 185) Supt. of Docs, no.: SI 1.27:185 1. Dolichopodidae. 2. Insects—Dominica. I. Title. II. Series: Smithsonian Institution. Smith- sonian contributions to zoology, no. 185. QL1.S54 no. 185 [QL537.D6] 591'.08s 595.7'71 74-23129 Contents Page Introduction 1 Key to the Genera of Dolichopodidae of Dominica 3 Subfamily Sciapodinae 5 Genus Condylostylus Bigot 5 Genus Sciapus Zeller . 15 Genus Leptorhethum Aldrich 19 Subfamily Neurigoninae 21 Genus Coeloglutus Aldrich 21 Genus Neurigona Rondani 22 Subfamily Medeterinae 25 , Genus Medetera Fischer von Waldheim 25 Genus Thrypticus Gerstacker 30 Micromedetera, new genus 37 Dominicomyia, new genus 39 Cryptopygiella, new genus 40 Subfamily Xanthochlorinae 42 Genus Xanthina Aldrich 42 Subfamily Enliniinae 46 Genus Enlinia Aldrich 46 Genus Harmstonia Robinson 58 Subfamily Peloropeodinae 60 Genus Discopygiella Robinson 60 Genus Micromorphus Mik 62 Genus Peloropeodes Wheeler 63 Subfamily Diaphorinae 66 Genus Achradocera Becker 66 Genus Asyndetus Loew 67 Genus Chrysotus Meigen 73 Genus Diaphorus Meigen 91 Genus Symbolia Becker 100 Subfamily Plagioneurinae 101 Genus Plagioneurus Loew 101 Subfamily Stolidosomatinae ..... 102 Genus Pseudosympycnus Robinson 102 Genus Stolidosoma Becker 103 Subfamily Sympycninae 105 Genus Sympycnus Loew 105 Subfamily Dolichopodinae 109 Genus Paraclius Loew 109 Genus Pelastoneurus Loew 116 Genus Tachytrechus Haliday 119 Subfamily Hydrophorinae 124 Genus Cymatopus Kert^sz 124 Genus Thinophilus Wahlberg 126 Literature Cited 127 Illustrations . 129 Index 140 BREDIN-ARCHBOLD-SMITHSONIAN BIOLOGICAL SURVEY OF DOMINICA The Family Dolichopodidae with Some Related Antillean and Panamanian Species (Diptera) Harold Robinson Introduction Survey there were no reports of the family Dolicho- podidae from the island of Dominica. The most Participants in the Bredin-Archbold-Smithsonian pertinent literature has been two papers by J. M. Biological Survey of Dominica have included many Aldrich on the Lesser Antillian islands of St. entomologists who have observed and collected Vincent (1896) and Grenada (1902) based on the samples of the extensive dolichopodid fauna of collections of H. H. Smith. More recently, a few the island. The author participated personally in initial results of the Survey have been published the first period of the Survey, from January to and these include the descriptions of Chrysotus April 1965, and other collectors included Dale F. mexicanus (Robinson, 1967a), Stolidosoma hexa- Bray of the University of Delaware, Paul J. Spang- chaeta and Pseudosympycnus perornatus (Robin- ler of the Smithsonian Institution, and Raymond son, 1967c), Harmstonia simplex (Robinson, J. Gagne, George C. Steyskal, and Willis W. Wirth 1967b), and, in addition, notes on the behavior of the U.S. Department of Agriculture. The special of Dominican species of Enlinia (Robinson, 1969). efforts of a number of the collectors are particu- The island of Dominica is a particularly favor- larly notable in the representation of the more able habitat for Dolichopodidae. Though the is- rarely collected smaller members of the family. It land has only 300 square miles, the terrain is pri- is hoped that the information presented here marily rough and moist. The island has two of covers most of the species of Dolichopodidae on the highest mountains in the Lesser Antilles, Dia- the island, and that it will furnish a guide for blotin (4661 ft) and Trois Pitons (4550 ft), and recognizing genera and species groups in many has hundreds of separate rivers and streams. The of the adjacent regions. Some results of studies on island has had limited disturbance and has retained Puerto Rican, Jamaican, and Panamanian species many areas of essentially virgin forest. In the years have also been included to increase the usability since the survey began there has been more dis- of the treatment. turbance and increased cutting of forests, but Previous to the Bredin-Archbold-Smithsonian effects on the Dolichopodidae of the island are not known. Harold Robinson, Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, A total of 113 species of Dolichopodidae in 30 D.C. 20560. genera is recognized from Dominica in the present SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY treatment, with 69 of the species described as new. Such a concentration of the genus in so small an This total compares with the approximately 1000 area seems unprecedented, but personal experience species previously described from the entire Neo- indicates that the discrepancy may result from tropical region (Robinson, 1970b). Of the 113 problems in collecting. In spite of a few definite species, the rate of endemism is uncertain. Most efforts, the author was unable to personally of the previously described species are widely dis- collect any of the many species of Thrypticus on tributed or at least known throughout the Lesser the island. Perhaps the members of the genus are Antilles. A few new species which are maritime subject to more seasonal fluctuations than most forms seem widely distributed. Still, most of the Dolichopodidae. In any case, the existing reports new species are probably restricted to Dominica of 26 species from the entire Neotropical region or to the series of closely adjacent islands, and they can hardly be a true indication of the status of do not seem to occur as far south as St. Vincent the genus. where other related species were collected by An important element of the dolichopodid H. H. Smith. Three new genera are described here fauna of Dominica consists of a number of rather from Dominica, but one of these is known also unrelated genera that