Thyreodon niger Cresson, 1874

Gauld, Ian D. & Janzen, Daniel H., 2004, The systematics and biology of the Costa Rican species of parasitic wasps in the Thyreodon genus-group (Hymenoptera: Ichneumonidae), Zoological Journal of the Linnean Society 141 (3), pp. 297-351 : 325-326

[ Thyreodon niger Cresson ; Porter 1976: 306. Misidentification, in part.]

Thyreodon apricus Porter, 1984: 57 . Holotype ♂, MEX- ICO (FSCA) [examined].

Fore wing length 17.9–20.4 mm; clypeus weakly convex, with apex bluntly pointed medially; malar space 0.5–0.6 times basal mandibular width; maxillary palp long with second palpomere both strongly broadened and flattened; lower face centrally punctate with weak coriaceous sculpture; frons with a raised area between antennal sockets but without distinct vertical crests; frons with a sharp carina extending from outer rim of antennal sockets upwards, close to and parallel with eye margin; frons centrally rugose; ocelli small, the lateral ocellus separated from eye by about 1.3–1.4 times its own maximum diameter; head in dorsal view with gena finely punctate, rather evenly rounded behind eye, occipital carina strong, its lower end sharp, not reaching hypostomal carina; antenna setaceous, with about 54 flagellomeres, the 20th slightly transverse, 0.8–0.9 times as long as broad, the subapical ones with setae which are slightly shorter than the diameter of the flagellomere. Pronotum short with anterior margin strongly and broadly reflexed, and with posterior margin centrally swollen, forming an angular, centrally impressed ridge which is separated from the anterior margin by a deep Ushaped groove; epomia present on upper part of pronotum as a weak keel extending under anterior reflexed margin; propleuron sparsely punctate, with lower corner flat, peripherally weakly rugulose; mesoscutum sparsely but coarsely punctate, with broad, moderately deep, reticulated notauli which are confluent posteriorly, inner anterior margin of notaulus forming a sharp transverse crest; scuto-scutellar groove very deep, laterally margined by a very strongly raised carina that is laterally slightly expanded; scutellum finely punctate, convex; mesopleuron polished and very sparsely punctate, without a sternaular impression; metapleuron transversely rugose; propodeum laterally flattened, finely reticulate/rugose, abruptly rounded above and behind the spiracle, with an indistinct ridge; propodeum posterodorsally finely reticulate, with transverse rugae posterolaterally, centrally with a broad fairly deep longitudinal impression, laterally flattened with a weak to moderate lateromedian longitudinal impression. Fore leg of female stout, with coxa with a large, bluntly rounded protuberance behind trochanteral insertion, with 5th tarsomere 0.7–0.8 times as long as preceding two tarsomeres, with tarsal claw long and closely pectinate; hind coxa in profile small, its hind end not quite reaching level of hind end of propodeum; hind femur stout, about 4.5–5.0 times as long as maximally deep; hind tarsus of male with very long coarse, sparse pubescence ventrally. Fore wing with abscissa of Cu 1a between Cu 1b and 2 m-cu 0.7–0.8 times as long as abscissa of Cu 1 between cu-a and 1 m-cu. Metasoma with tergite I slender, anteriorly slightly laterally compressed; tergite II, in lateral view, 2.1–2.2 times as long as posteriorly deep. Male with subgenital plate small and rather flat, covered with coarse hair; claspers long, the dorsal apex produced into a spine-like projection, the lower margin not angulate before apex; aedeagus in profile slender, with apex simply up-turned.

A shining black species without a noticeable metallic reflection; flagellum blackish brown, lighter in ♂ wings uniformly blue-blackish.

Remarks: Thyreodon apricus superficially closely resembles T. deansi , which also is non-metallic black and has three longitudinal grooves on the propodeum. However, the two species differ in many features. T. apricus lacks the strong frontal crests present in T. deansi , and has the vertex more finely punctate. T. apricus also has the metapleuron transversely rugose rather than finely closely punctate, and it lacks the gap in the pecten of the fore tarsal claws. The males differ in that T. apricus has very long sparse pubescence on the hind tarsus, whereas that of T. deansi is much shorter and denser.

Biological notes: Thyreodon apricus is a widespread Mesoamerican species that ranges from the southern part of Texas, southwards to north-western Costa Rica. It seems to be restricted to areas with a strong dry season. Porter (1984) remarks that he collected this species in Texas under sparse Acacia , in Celtis woodlands and around Prosopis and Pithecellobium groves. This species has been reared only once by the ACG caterpillar and parasitoid inventory [87-SRNP-1319], from a last instar larva of Erinnyis lassauxii (Sphingidae) feeding on Macroscepis obovata (Asclepiadaceae) . A second caterpillar of the same species produced an identical Thyreodon cocoon but the wasp died without developing. Both records are from the ACG dry forest ( Janzen & Hallwachs, 2003). The parasitoid larva killed its host in the pupation retreat, then spun a cocoon from which the adult wasp emerged about 1 month later.

As more than 15 000 other sphingid larvae (including 1400+ members of the genus Erinnyis ) of about 65 species (including six species of Erinnyis ) have been reared from the ACG dry forest, we feel comfortable in concluding that Erinnyis lassauxii is probably the sole species attacked by T. apricus . E. lassauxii , with a range from the south-western USA to Argentina ( D’Abrera, 1986), easily covers the dry forest geographical and ecological range of T. apricus .

Material examined: Holotype ♂, MEXICO, Mexico, Chalma , vi.1974 (Porter) ( FSCA) . Paratypes: HONDU- RAS: 1 ♀, Puerto Castillo, iii.1924 ( USNM) . MEXICO: Chiapas: 1 ♀, Cachuatil, c. 50 km SW Cintalapa , 500– 700 m, viii.1965 (Weems) ( FSCA) : Tamaulipas: 2 ♂, nr San Antonio on ruta 101, vi.1982 (Porter) ( FSCA) . USA: Texas: 2 ♀, Hidalgo Co., Bentsen Rio Grande Valley State Park, iii–v.1977 (Porter) ( FSCA) .

Non-type material: COSTA RICA: Guanacaste Prov.: 1 ♀, Guanacaste National Park, Finca Jenny, 31 km N Liberia, 240 m, vi.1994 (Araya) ( INBio ); 1 ♀, Guanacaste National Park, reared as per data above (Janzen & Hallwachs) (JHVC); 1 ♀, Guanacaste National Park, Estacion Los Almendros, 300 m, vi.1995 (Lopez) ( INBio ); 1 ♀, 1 ♂, Santa Rosa National Park, 300 m, vi.1985 (Janzen & Gauld) (BMNH); 1 ♀, same locality, 300 m, vi.1992 (Parataxonomists) ( INBio ); 1 ♀, 1 ♂, same locality, 300 m, vi.1992 ( Pereira ) ( INBio ).