ECOLOGY, ZOOGEOGRAPHY AND TAXONOMY OF THE 
LOWER RIO GRANDE VALLEY MESOSTENINES 
(HYMENOPTERA, ICHNEUMONIDAE) 
By Charles C. Porter 1 
Department of Biological Sciences, Fordham University 
Bronx, N.Y. 10458 
Introduction 
This study analyzes results of five years’ fieldwork with net and 
Malaise Traps on mesostenine ichneumonids of semiarid subtropi- 
cal scrub and moist gallery woods habitats in the Lower Rio Grande 
Valley of south Texas. It lists 18 genera and 35 species. The genus 
Bicristella and the species Trachysphyrus mesorufus, Cryptanura 
lament aria, and Lymeon leucosoma are recorded for the first time 
from the United States. Cryptanura vallis Mesostenus opuntiae, 
Bricristella texana, Diapetimorpha sphenos, D. aspila, and D. pareia 
are described as new. The zoogeographic relationships, phaenol- 
ogy, and habitat preferences of each taxon are recorded and con- 
clusions are adduced as to distributional patterns, annual cycles, 
habitat selection, and diversity of the entire south Texas mesoste- 
nine fauna. The south Texas fauna also is compared with meso- 
stenine communities of other semiarid parts of the Neotropics, such 
as the Peruvian Coastal Desert and the northwest Argentine Sub- 
andino, and all these relict or marginal xerophilic faunas are dis- 
cussed with regard to their origin in wet forest centers of ichneu- 
monid radiation. 
Acknowledgements 
Major support for this research was provided in 1 976— ’77 by a 
National Science Foundation Grant (DEB 75-22426) and during 
1973-75 by grants from the Committee for Research and Explora- 
tion of the National Geographic Society. Mr. David Riskind and 
Mr. Sim Oefinger, Jr. of the Texas Parks and Wildlife Department 
issued permits for insect collecting in the Bentsen Rio Grande Valley 
State Park. At Bentsen Park, Mr. Reynaldo Ortiz (Superintendent) 
'Research Associate, Florida State Collection of Arthropods, Florida Department 
of Agriculture and Consumer Services, Gainesville, Florida 32602. 
Manuscript received by the editor, May 24, 1977 
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