Megaselia alajuelensis (Malloch 1914)

Megaselia (Megaselia) alajuelensis (Malloch)

Aphiochaeta alajuelensis Malloch, 1914, p. 32 [♂ ♀; Costa Rica].

Megaselia (Megaselia) alajuelensis (Malloch).—Borgmeier, 1962b, pp. 309, 410, fig. 91 [Costa Rica; Brazil].

Holotype male and paratype female, Alajuela, Costa Rica (ANSP); 1 paratype male (CTB).

MALE.—Length 1.00–1.80 mm. Frons subquadrate, as broad as long medially, somewhat shorter laterally, yellow or brown, pubescent, with a distinct median line. Lower su weak, about one-half in length of the upper which are one-fourth of frontal width apart. Antials very close to anterolaterals, inside of them and slightly lower; 2nd row slightly convex, the bristles equidistant. Third antennal joint brown, globose, of normal size; arista one-third longer than width of frons. Palpi yellow, with long bristles.

Thorax yellow. Mesopleura bare. Scutellum with 2 bristles and 2 hairs.

Abdomen: venter yellow. Tergites brown, 6th sometimes yellow. Pubescence short, hairs on hind-margin of 6th bristle-like. Venter with transverse apical rows of conspicuous bristly hairs on segments 3–6. Hypopygium (Figure 113) pale brown, small, hairy, hairs short or of moderate length. Anal segment short, yellow, with short hairs, end-hairs not differentiated.

Legs entirely yellow, hind femur not darkened at tip. Foretarsus slender. Hind femur ventrobasally with about 7 longish curved hairs. Hind tibia with 12 fine setulae, those below middle somewhat stronger.

Wing (see Borgmeier, 1962b, fig. 91), grayish, yellow, veins dirty yellow. Costa 0.52 of wing length, ratio of segments (in paratype) 10:8:3. Cilia moderately short (0.07–0.08 mm), there are 6 pairs between 1st vein and tip of costa; 3rd vein without a bristle at base; 4th vein starting at fork; 5th and 6th sinuous. Axillary margin with 3 hairs. Anal margin broadly convex. Halteres brown.

FEMALE.—Length 1.10–2.00 mm. Similar to male. Proboscis (Figure 114) narrow, yellow. Tergites (Figure 112) pale brown, subsequal in length; hind corners of 5th broadly rounded; lateral borders of 6th convex. Pubescence conspicuous on lateral borders of tergites; 2nd with bristly hairs. Venter sparsely hairy, hairs shorter than in male. Costa 0.52–0.53 of wing length; there are 7–8 cilia between 1st vein and apex of costa.

MATERIAL EXAMINED.—Besides the types from Costa Rica and numerous specimens from Brazil, I saw about 300 specimens from Dominica: 25 pinned specimens, 48 on slides, and more than 200 in alcohol, from the following localities: Clarke Hall, Pont Casse, Manets Gutter, Fond Figures R.., d’Leau Gommier, S. Chiltern Est. (W. W. Wirth; O. S. Flint; T. J. Spilman; 1964–1965).

VARIATION.—The variation in body-length is remarkable.