A NEW ARBORICOLOUS THYREODON 
FROM COSTA RICA 
(HYMENOPTERA ICHNEUMONIDAE: OPHIONINAE). 
By Charles C. Porter 1 
Department of Biological Sciences, Fordham University 
Bronx, NY 10458 
Through courtesy of Daniel H. Janzen of the Department of 
Biology at the University of Pennsylvania, I have received for study 
a new Thyreodon of the Atricolor group (Porter 1984), reared by 
him in Costa Rican Tropical Deciduous Forest at Santa Rosa Na- 
tional Park. I herewith describe this ecologically aberrant Thyreodon. 
1. Thyreodon santarosae Porter, new species 
(Figs. 1, 2) 
Female. Color : antenna varying from almost all black to exten- 
sively dusky, brown, or dull yellowish brown; head and body shin- 
ing black to brownish black (more lustrous on gaster) and with 
variably developed, diffuse, dull to (occasionally) light brown stain- 
ing that usually is best developed on mandible and on gastric ter- 
gites 2 and 3 in part; legs sometimes entirely black or often with 
variable brownish suffusion on coxae and trochanters, trochantelli 
and femora shining medium brown with some dusky staining, and 
tibiae and tarsi dull pale brown with dusky only on last tarsomere; 
wings varying from almost entirely blackish to subdued golden yel- 
low with blackish on apical 0.3 of fore wing, sometimes also near 
base of fore wing, as well as on apical 0.3 of hind wing and conspic- 
uously (but often not extensively) in anellan cell of hind wing. 
Length of fore wing: 15.6-19.0 mm. Flagellum: with 57-60 seg- 
ments; 1st segment 2.0-2. 3 as long as deep at apex. Mandible: with 
numerous, medium sized to large, basally denser, but mostly well 
discrete punctures. Malar space: 0.54-0.63 as long as basal width of 
mandible. Temple: 0.70-0.88 as long as eye in dorsal view; rounded 
'Research Associate, Florida State Collection of Arthropods, Florida Department of 
Agriculture and Consumer Services, Division of Plant Industry, P.O. Box 1269, 
Gainesville FL 32602. 
Manuscript received by the editor September 20, 1985 
133 
