1976] 
Porter — Thyreodon from South Texas 
305 
spilini of the Subfamily Ophioninae. Townes (1966, p. 185-191) 
lists 24 species for the Neotropic Region but only three species 
currently are cited from America north of Mexico (Hooker, 
1912, p. 122; Muesebeck, Krombein and Townes, 1951, p. 401). 
Of these latter, T. atricolor inhabits the whole eastern U.S. and 
southern Canada and also has been recorded from Arizona, T. 
fernaldi is known from Colorado and Arizona, and T. ornatipen- 
nis from New Mexico. 
T. atricolor has been reared from sphingid moths of the genera 
Lapara and Paonias (Hooker, 1912, p. 120-121). There are no 
host records for other Thyreodon but their large size makes it 
probable that they likewise attack sphingid or similar bulky 
lepidopterous larvae. 
Many Thyreodon occur in subtropical or tropical forests, 
usually below 2000 m., but quite a few species also extend into 
deciduous forest, thorn scrub, savannas, and other drier habi- 
tats. Their ability to adapt to climates more arid than those favored 
by most ichneumonids probably explains the penetration of 
T. niger and T. latieinctus into the subtropical thorn scrub and 
semidesert of south Texas. 
Key to the South Texas Thyreodon 
1. Black with flagellum mostly yellow and gastric tergites 3-4 
largely ferrugineous; notaulus defined as a very shal- 
low band of relatively fine puncto-reticulation, with 
a weak and appressed crest at front end; mesopleuron 
finely and densely punctate throughout; hind face of 
propodeum uniformly reticulate with only faint traces 
of a median channel and lateral depressions 
1 . T. latieinctus. 
Almost entirely black; notaulus strongly impressed and 
coarsely foveolate, with a conspicuously raised crest 
at front end; mesopleuron uniformly smooth, polished, 
and practically impunctate; hind face of propodeum 
with a deep, transversely wrinkled median longitudinal 
channel and two broader and shallower but also strong- 
ly trans-rugose lateral depressions, which are separated 
from the median channel by a pair of broad and high, 
mostly smooth and polished longitudinal elevations .... 
2. T. niger. 
