Simulium (Hearlea) menchacai Vargas & Díaz Nájera

Figs. 6J, K

Simulium (Hearlea) menchacai Vargas & Díaz Nájera, 1957: 208–210, Figs. 170–178; Díaz Nájera & Vulcano, 1962: 101–102, Figs. 85–88.

Female: Wing length, 3.5 mm. General coloration blackish. Thorax blackish brown; scutum with abundant appressed silvery pilosity that somewhat obscures submedian silvery stripes; vittae not adjoining 1+1 anterior subtrapezoidal silvery spots; scutellum brownish, metanotum and pleurae blackish; legs yellowish brown. Abdomen mostly brownish, with tergites II–IV pale. Fronto­ocular triangle about as long as high. Metathoracic basitarsus 0.5–1.1 times longer than broad. Cibarium wrinkled, with anterior margin thickened, translucent, medially concave, without lateral subovoidal prominences; Sc with 15–17 setae. Genitalia as in S. larvispinosum .

Male: Wing length, 3.0 mm. Coloration blackish; scutum velvety black with anterior area whitish. Sc with 2–3 trichomes. Hind basitarsus 3.0–3.1 times longer than broad. Genitalia similar to those of S. larvispinosum .

Pupa: Length: basal, 3.5 mm; dorsal, 3.0 mm. Cocoon slipper shaped, loosely woven, closed basally, with reinforced anterior margin coarse and slightly projected dorsolaterally. Gill well sclerotized, cylindrical, comprised of 9–10 terminal branches; 3 primary gill branches: dorsal one short, oriented posteriorly, and curved with rounded apex; median branch short, with 3 secondary branches of approximately equal length; dorsal secondary branch bifurcated basally, median secondary branch subdivided apically into 3 branches, third secondary branch also with 3 subdivided branches, although on different plane; primary ventral branch curved and longer than other three main branches (Figs. 6J–K). Secondary branches are apically accuminated. Frontoclypeus smooth, with robust spiniform setae, frontal ones divergent and superíor ones very long. Thorax with abundant, small, rounded granules.

Larva: (Diagnosis derived from Vargas & Díaz Nájera, 1957 and also from Díaz Nájera & Vulcano, 1962). Length (mature), 7.5–8.0 mm. Coloration dark greenish. Cephalic apotome homogeneously pigmented, without discernible headspots. Labral fan with 50–55 primary rays. Hypostoma with anterior margin curved and 15–17 lateral setae per side. Postgenal cleft dome shaped, with anteromedian incision. Anal sclerite, accesory plates and ventrolateral papillae similar to those of S. gorirossiae, but with ventrolateral plates having shorter, more anteriorly directed accuminate projections. Posterior circlet with ca. 310 rows of hooks. Rectal papillae trilobed, with 6–12 lobules per lobe (18–36 total).

Material examined: México: Oaxaca, Cerro San Felipe del Agua, 2 pharate female and 1 pharate male (on slide), 3 pupae, 13 May 1962, Reyes & Vulcano (MLP) leg. INDRE .

Distribution: México: Oaxaca.

Discussion: The larva is very close to those of S. gorirossiae and temascalense, based upon similar anal sclerite and accessory plates morphology, and presence of ventrolateral papillae on the larva. However, the peculiar form and disposition of the pupal gill branches permits their separation.