Anthrax gideon Fabricius 1805

Anthrax gideon Fabricius

Anthrax gideon Fabricius, 1805, p. 124.—Wiedemann, 1828, p. 311.—Macquart, 1840, p. 342.—Osten Sacken, 1858, p. 40.—Curran, 1934, p. 363.—Wolcott, 1951, p. 450.

Argyramoeba gideon.—Schiner, 1868, p. 122 [Argyromoeba].—Osten Sacken, 1878, p. 90—Kertész, 1909, p. 64.

Spongostylum gideon.—Aldrich, 1905, p. 233 [Spogostylum].—Johnson, 1913, p. 56 [Spogostylum].

Anthrax acroleucus Wiedemann, 1828, p. 312 [acroleuca].—Curran, 1934, p. 363 [acroleuca].

Argyramoeba acroleuca.—Osten Sacken, 1886, p. 101.—Kertész, 1909, p. 59.

Spongostylum acroleucum.—Williston, 1901, p. 275 [Spogostylum acroleuca].—Aldrich, 1905, p. 222 [Spogostylum acroleuca].—Johnson, 1913, p. 56 [Spogostylum acroleuca].

Argyramoeba sp.—Osten Sacken, 1886, p. 101.

MALE.—Integument mostly black, legs and pleura often brown; front, mesonotum, scutellum, and abdominal terga velvet black or brown pruinose, remainder of body brown or gray pruinose. Setae and scales on front black; face with black setae extending to antennae, a few white hairs ventrally. Setae and scales on occiput black; fringe of pile on posterior margin black. First antennal segment about as long as apical width; second segment globular; base of third segment globular (often collapsed), slightly smaller than second segment, narrowing abruptly to styliform part which is about one-half longer than base and about one-third longer than style (Figure 117).

Discs of mesonotum and scutellum with short black setae and threadlike black scales; lateral and anterior margins of mesonotum with longer black hairs, erect linear scales, and black setae. Stemopleuron, mesopleuron, and anterior half of pteropleuron with fine black setae and threadlike black scales, some dorsal long black hairs and coarse black setae on mesopleuron and pteropleuron. Prosternum and propleuron with black pile; postalar tuft of pile black. A patch of black hairs often behind spiracle. Coxae with black hairs, setae, and threadlike scales.

Wing (Plate 4i) pigmented velvet black or brown basally, hyaline apically; apical margin of pigment distinct, running from tip of vein R1 across base of cell R4 to vein M1 slightly beyond base of cell Ml, basally on vein R5 to slightly beyond r–m crossvein and thence curving posteriorly through extreme base of cell 2M2 to tip of vein 1A; usually a narrow hyaline area posteriorly in cell R5. Basal angles of veins R4 and R2+3 without spurs, or having spurs shorter than basal segments of veins. R–M crossvein located at basal third or two-fifths of vein M1+2; contact of cells 1M2 and Cu1. about equal to base of cell Cu1. Posterobasal part of wing not narrowed, cell 2A slightly wider than cell 1A, alula rounded posteriorly. Apex of wing often milky colored as far back as tip of vein R1. Stigmatic area heavily pigmented. Calypter pigmented, fringe of hairs usually white in specimens from northern South America and Central America, usually black or brown in specimens from southeast Brazil. Halter brown, extreme tip of knob yellow.

Scales on legs black. Middle femur without macrochaetae anteroventrally or with only one or two short ones; hind femur with three to five weak macrochaetae anteroventrally; hind tibia with single row of macrochaetae anterodorsally.

Sides of abdominal terga with dense black pile; sterna and discs of terga with sparse black setae and black, threadlike scales.

MALE GENITALIA (Figure 63).—Gonocoxites broad, dorsal margins curving concavely to ventral margins to form acute apices in lateral view; apices broadly rounded in ventral view, with sharp ridges mesally. Basal segment of gonostylus sharply pointed basally, convex toward apex in lateral view; distal segment round in cross section basally, tapering apically; sharp longitudinal ridge dorsally in lateral view; apex sharply bent upward and outward, or straight in some specimens from eastern Brazil. Setae on gonocoxites extending almost to base, evenly distributed, absent at extreme apices; setae over interior and ventral surfaces of basal part of distal segment of gonostylus. Apex of epiphallus with a basally acute, apically emarginate dorsal plate formed at about a 30° angle; ventrolateral part broad, not extending to apex of dorsal plate; dorsal bands very narrowly separated medially, without setae. Base of aedeagus broad, but not bulbous, tapering only slightly to junction with ventral bands below junction of dorsal bands.

FEMALE.—Similar to male. Fringe of hairs on posterior margin of occiput sometimes white below. Pile on prostemum, propleuron, anterior half of mesopleuron, and anterior margin of mesonotum occasionally partly or wholly white. Apices of wings never milky. Sides of first and anterior half of second abdominal terga often with white pile. Sides of fourth tergum occasionally with a patch of long, overlapping, acute silver scales, and a few white seta.

FEMALE GENITALIA (Figure 94).—Tenth tergum with about 18 spines on each side. Ventral arm of ninth tergum narrow, parallel sided and nearly straight, apex not enlarged. Dorsomedial angle of sclerite on each side of gonopore produced mesally as a short narrow, truncate lobe; lateral arm broad basally, tapering to an acute apex, curled under below; ventral arm narrow and curved sharply inward below. Each spermathecal duct about four times as long as bulb; first section very short; middle section slightly shorter than apical section which is about twice as long as bulb and broadly expanded almost to width of bulb apically; bulb asymmetrical, slightly longer than maximum width, constricted at junction with duct.

DISTRIBUTION AND ECOLOGY.—Anthrax gideon occurs from southern Mexico into the Guianas and Bolivia in northwestern South America, and in the Serra do Mar in southeast Brazil (Map 23). Two specimens were collected by the author in Rio de Janeiro, Brazil, along the edge of an open sand and gravel area in the tropical forest covering the mountainous southwestern part of the city. No specimens of this species have been seen from the Amazon Basin, nor from the extensively collected Barro Colorado Island in the Canal Zone, Panama. This may indicate that gideon inhabits areas of greater relief, which would explain its discontinuous distribution.

MAP 23.—Distribution of Anthrax gideon.

TYPES.—According to notes made by Painter and Painter, there are two females of Anthrax gideon Fabricius in the Universitets Zoologiske Museum, Copenhagen. One carries the red type label only, while the other carries the red type label and another label reading “A. gideon ex Am. Mer. Schmidt.” A homotype compared with the type is typical of female specimens from Central America and northwestern South America.

Painter and Painter (personal notes) found a series of syntypes of Anthrax acroleuca consisting of five males and one female in the Vienna Museum. All are apparently from Brazil. No lectotype was chosen since none of the specimens was perfect nor complete. A homotype compared with the type series is typical of specimens from southeast Brazil.

The type female of Argyramoeba propinqua Schiner is in the Vienna Museum. According to notes made by Painter and Painter, it carries the labels “Venezuela” and “propinqua Alte Sammlung.” The specimen is partly glued together and greasy, with the antennae plastered down or missing, the last pair of legs missing, and one wing broken. The photograph and redescription of the type indicate that it is a typical specimen of the form propinquus discriminated below.