Orgilus obscurator (Nees 1812)

Orgilus obscurator (Nees)

Microdus obscurator Nees, 1814, p. 186, pl. 4: fig. 1.

Orgilus obscurator (Nees).—Haliday, 1833, p. 262.—Marshall, 1885, p. 278, pl. 6: fig. 6.—Thorpe, 1930, p. 401.

Ischius obscurator (Nees).—Wesmael, 1837, p. 21, fig. 10.—Ratzeburg, 1848, p. 46.

Eubadizon leptocephalus Hartig, 1838, p. 268.

Macropalpus leptocephalus (Hartig).—Ratzeburg, 1844, p. 57, pl. 7: fig. 9.

Macropalpus laticephalus Kolenati, 1859, p. 47.

This species is most like buccatus, new species, and longiceps Muesebeck. From both it is readily distinguished, however, by its nonflaring temples. It differs further from buccatus in having well developed though short longitudinal carinae arising from the posterior margin of the propodeum, and from longiceps in its darker legs. Orgilus dioryctriae Ganan, which obscurator resembles superficially, has flaring temples and a wider face, and its propodeum lacks the apical carinae.

FEMALE.—Length around 4.5 mm. Head a little narrower than thorax, in dorsal view about 1.5 times as wide as long, rather strongly evenly excavated behind; face at narrowest point slightly narrower than eye height and coarsely punctate to rugose punctate; clypeus as long as malar space, more weakly punctate than face; malar space less than 0.4 as long as eye height; anterior tentorial pits clearly below level of lower eye margins; cheeks and temples smooth and shiny with only very minute setigerous punctures; temples neither flaring nor receding but evenly rounded and very slightly narrower than eyes; ocellocular line hardly one and one-half times as long as diameter of an ocellus and shorter than the distance between lateral ocelli; antennae about as long as the body, 30- to 34-segmented in the specimens examined, even the segments of the apical fourth of flagellum slightly longer than broad; maxillary palpi short, hardly as long as height of head.

Thorax stout; mesoscutum with numerous minute and very shallow punctures on middle lobe; notauli sharp and completely, finely foveolate; propodeum strongly rugose, narrowly smooth and polished each side of the middle at base, and with short longitudinal carinae arising from the posterior margin and setting off five apical areas that are open in front; lateral face of pronotum granular and dull anteriorly, rugulose below posteriorly and in the impression, punctate and shiny along the upper margin; mesopleuron smooth and polished, the longitudinal furrow coarsely foveolate; metapleuron rugose at lower posterior margin, smooth and shiny elsewhere although sometimes with scattered shallow punctures over most of its surface. Hind coxa strongly rugulose on upper edge, more weakly rugulose to granulose on outer side; hind femur hardly four times as long as wide; inner calcarium of hind tibia slightly more than half as long as metatarsus; tarsal claws simple. Radial cell on wing margin hardly as long as stigma; second abscissa of radius on a line with intercubitus; stub of third abscissa of cubitus a little longer than second abscissa, which is about half as long as intercubitus; nervulus usually interstitial or nearly so; hind wing less than 4.5 times as long as wide; lower abscissa of basella longer than nervellus but less than half as long as mediella.

Abdomen nearly as broad as thorax; first tergite about 1.2 times as long as wide at apex, smooth at extreme base, usually closely finely rugulose behind the spiracles but occasionally with the smooth area extending caudad beyond the spiracles; second tergite much broader than long, finely rugulose or rugulose punctate, more weakly so apically, the apical third sometimes largely smooth; second suture fine but rather sharply impressed; third tergite sometimes with a little weak rugulosity or punctation on basal half but often entirely smooth and polished; ovipositor sheath about as long as the distance from base of scutellum to end of abdomen.

Black; antennae, palpi, tegulae, and wing bases black; apices of anterior and middle femora, their tibiae, the posterior tibiae except at apices, and bases of the posterior metatarsi, reddish; wings uniformly a little infumated.

MALE.—Like the female in essential characters.

DISTRIBUTION.—The foregoing redescription is based principally on numerous specimens in the U.S. National Museum that were reared from the pine-shoot moth, Rhyacionia buoliana (Schiff.), in Austria, and on long series of both sexes received from the Forest Insect Laboratory, Canada Department of Agriculture, at Sault Sainte Marie, Ontario, all of which had been reared from R. buoliana taken at Paris, Dunnville, London, and Port Dover, Ontario. The U.S. National Museum also has specimens from Switzerland, Spain, France, Germany, and England, and United States specimens from Michigan, Ohio, Connecticut, and West Virginia. In addition I have seen material in the Canadian National Collections from Suffolk and Hampshire, England, and from Ottawa, Niagara Falls, and Cedar Bay, Ontario. The species is widely distributed in Europe. In 1928 it was introduced into Canada (McGugan and Coppel, 1962, p. 70) to aid in the control of R. buoliana, which had become a serious pest in parts of Ontario; and it has become well established there. Soon afterward (Dowden, 1934, p. 599) it was imported from Europe by the U.S. Department of Agricuture for liberation in infestations of the pine-shoot moth in New England, and it is now well established in the United States.

Thorpe (1930) lists ten species of Tineidae and Tortricidae, in addition to R. buoliana, as recorded hosts of O. obscurator in Europe; and the card index to published host-parasite associations, which is maintained by the Insect Identification and Parasite Introduction Branch of the United States Department of Agriculture, includes records of six additional host species not listed by Thorpe. I seriously doubt, however, that all, or even most, of these records are correct, for species of Orgilus are not easily identified accurately. I have seen no specimens of the parasite from any host other than R. buoliana.