Pachyneurella venata (Aldrich 1896)

Pachyneurella venata (Aldrich)

Phora venata Aldrich, 1896, p. 436 [♂; St. Vincent, W. I.].

Pachyneurella venata (Aldrich).—Brues, 1904 p. 382, pl. IX: figs. 58 [wing], 59 [hypopygium].

Puliciphora venata (Aldrich).—Brues, 1906, p. 15; 1919a, p. 506; 1923, p. 22 [♂ ♀, Grenada; not Bolivia].—Borgmeier, 1960, p. 336 [in part; not ♀, not fig. 97 = bicolor].

Lectotype male, herewith designated (USNM) and 1 paratype male (MCZ), from St. Vincent, B.W.I. (Aldrich). Probably 1 “type” also in British Museum, London (teste Brues, 1904, p. 382).

MALE.—Length 1.0–1.3 mm. Frons broader than long laterally (3:2), black-brown, opaque, sparsely pubescent, without median furrow. There are 4 equal porrect supraantennals and 2:4:6 bristles; anterolaterals wanting; Antials inclined toward median line, close to mediolaterals; 2nd row concave anteriorly. Jowls-cheeks with an ascending row of 5 bristles. Third antennal joint dark brown, globose, of normal size; arista apical, distinctly pubescent. Palpi yellowish brown to dark brown, narrow, with short bristles.

Thorax dark brown, opaque. Two dorsocentrals. Mesopleura bare. Scutellum with 2 bristles.

Abdomen black-brown to black, dull. Second tergite a little elongated, tergites 3–6 subequal in length, 6th tergite followed by a membranous yellow apical band which partly covers the hypopygium. Pubescence short, 6th segment laterally and ventrally with hairs placed in chitinous spots. Hypopygium (Figures 141–142) castaneous, large, asymmetrical, longer than high, at left behind with a long black process which is somewhat flattened, and at right with a pale process; at left above there is a single bristle near the base of the anal tube; and at right there are apically about 6 bristly hairs. Anal segment large, depressed, the tergites laterally on each side with 4 strong bristles; apical hairs of ventrite inconspicuous.

Legs yellowish brown, forecoxae paler. Foretarsus slender, metatarsus slightly concave on anterior border, but not suddenly constricted as in Pachyneurella bicolor. End-spur on mid- and hind tibia short. Hind tibia without hair-seam and without cilia. Hind metatarsus with 5 transverse combs of hairs.

Wing (Figure 140) brownish yellow, veins dark brown. Length 1.37 mm, width 0.67 mm. Costa 0.54 of wing length, ratio of segments 2:3; 1st section at distal 3rd with a small swelling. Costal cilia very short and close. Fourth vein nearly straight; 5th but little curved before middle, remainder nearly straight; 6th slightly sinuous. Axillary margin without hairs. Halteres dark brown.

FEMALE (undescribed).—Length 1.2 mm. Frons transversely convex, pale brown to dark brown, shining, pubescent, with 4 supraantennals and 4 bristles on vertical border. Three ocelli. Eyes somewhat reduced, about twice as long as 3rd antennal joint; the latter is brown, globose, pointed; arista apical, distinctly pubescent. Palpi brown, with long bristles.

Thorax short, about twice as broad as long, shining, reddish yellow or yellowish brown, lighter than head. Prothoracic bristle wanting. Hind corners without alar papilla. Hind border with 6 bristles, the 2 inner ones close together, the sublateral close to the lateral, the latter placed a little more cephalad, the sublateral in line with the inner bristles. Abdomen strongly convex, shining. Venter fuscous; the 6 tergites deep black castaneous; the structure of the tergites more or less as in Pachyneurella bicolor, 6th very small; 5th with a small gland opening basally, with a small raisable flap covering it. Pubescence short, distinct, yellowish; hairs on membranous parts of segments 4–6 partially placed in dark chitinous spots. Cerci distinct. Legs yellow.

MATERIAL EXAMINED.—Besides the types (USNM, MCZ), I have seen 23 males and 2 females from Dominica: Clarke Hall, Manets Gutter, Pont Casse, Sylvania, Trafalgar Falls, d’Leau Gommier, Fond Figues R., South Chiltern Est., Macoucheri, I.–III. 1965 (W. W. Wirth).