Simulium (Hearlea) burchi Dalmat

Coscarón, S., Esquivel, D. R. Miranda, Moulton, J. K., Arias, C. L. Coscarón- & Bernal, S. Ibañez, 2004, Simulium (Hearlea) Vargas, Martínez Palacios, & Díaz Nájera (Diptera: Simuliidae): Taxonomic revision and cladistic analysis, Zootaxa 396, pp. 1-52 : 11-12

Simulium (Hearlea) burchi Dalmat

Figs. 5A, B

Simulium (Hearlea) burchi Dalmat, 1951: 44 (1): 42–47, Figs. 16–23; 1955: 72, 82, 87, 239–244, Figs. 94–96, 214–216, 251, 308, 348, 386, 423.

Female: Wing length, 2.9–3.1 mm. General coloration brown­blackish. Frons and clypeus light brown with silver pollinosity; scutum velvety brown­blackish, with 1+1 silvery submedian vittae not adjoining anteriorly with 1+1 subquadrangular silvery pruinose spots and posteriorly with whitish pruinose prescutellar area; lateral and anterolateral borders with silver bands; scutum pilosity dense, golden to silvery greenish. Pleurae light graybrown, with silver pollinosity. Legs yellowish brown, with apices of femora, tibiae, and tarsomeres dark brown. Wing veins pale brown. Abdomen brownish, with tergite II silvery; tergites VI–IX cereus. Cibarium concave medially, slightly indented. Sc pilose. Genitalia similar to those of S. capricorne .

Male: Wing length, 3.0– 3.1 mm. Scutum velvety black bordered by silvery band along periphery and with faint silvery pruinosity along anterior 1/4. Legs as in female, but apices of femora, tibiae, and tarsomeres black. Sc bare. Hind basitarsus 3.9 times longer than broad. Genitalia with basistylus having rounded internal protuberance; dististylus elongate, ratio of dististylus length/basistylus length = 2.1; ventral plate with small median carina similar to that of S. delatorrei ; endoparameres with numerous, strong hooks.

Pupa: ( Figs. 5A, B ). Cocoon shoe shaped, with weak texture woven and reinforced anterior margin; length at base 3.8 mm, dorsal length 2.8 mm. Frontoclypeus smooth, lacking granules. Thorax with moderate number of granules. Gill strongly pseudoannulated, especially medial branch, comprised of 3 primary branches; medial branch largest (length, 1.4–1.5 mm), distally capitate, with small tubercles dorsally and apically; ventral branch medium­sized (length = 1.0 mm) compared to other branches, flattened, with peculiar longitudinal crest along internal margin; dorsal branch small, 1/5 or less length of other branches. Abdominal tergite X without terminal spines.

Larva: Length (mature), 7.3 mm. General coloration gray to tan. Cephalic apotome with narrow dark median stripe basally. Labral fan with 46–54 primary rays. Antenna surpassing stalk of labral fan; ratio of antennal articles = 1.0:1.5:1.0 (proximal: medial: distal). Hypostoma with median and corner teeth longer than others, 14–15 lateral setae per side, and 3+3 discal setae. Postgenal cleft dome shaped, with narrow median anterior incision; ratio length of hypostoma/length of hypostomal bridge = 1.1:1.0. Lateral plate of prothoracic proleg with 47–50 setae. Posterior circlet with 172–178 rows of 20–24 hooks. Rectal papillae with ca. 78 lobules, 22 on dorsal (central) lobe and 28 lobules on each lateral lobe. Anal sclerite simple.

Material examined: Guatemala: (Dalmat collection, USNM), El Quiché, Nebáj, río Micovez , male (allotype on slide) 1 pupa, 2 pupal exuviae, 15 November 1949 , Ochoa & H. Dalmat; same, 1 male; 2 females (paratypes), 5 pupae, 16 November 1949 ( Dalmat ) ; 10 males, 15 November 1950, H. Dalmat; 1 male, 28 March 1951, H. Dalmat ; 1 male (without abdomen), 30 August 1951, H. Dalmat; Huehuetenango, Cuilco, río Yulva , 2 pupal exuviae (paratypes), several larvae and pupae (paratypes), 29 February 1949 .

Distribution: Guatemala: El Quiché and Huehuetenango.

Bionomics: This species occurs in medium­sized torrenticolous creeks on stones, leaves, and twigs.

Discussion: This species resembles to S. dalmati based upon the pupal gill, but the gill of S. dalmati has a more uniform only slightly distally expanded dorsal branch and a longer ventral branch. The cocoon of the somewhat similar S. burchi is more shoe shaped and coarsely woven. Females of S. dalmati have the 1+1 silver anterior spots subtriangular in shape and adjoining vittae that extend further posteriorly. The original description of S. burchi states that the vittae join the anterior 1+1 subquadrangular spots, but in the two pinned paratypes from the USNM, the vittae do not fully adjoin them. Larvae of S. dalmati differ from S. burchi by their larger size, longer hypostomal bridge (index of 0.8), and smaller number of lobules on the rectal papillae.

Figures

FIGURE 5. Pupa and respiratory organ. A, B. S. (H.) burchi; A. lateral view, B. dorsal view. C–F. S. (H.) delatorrei; D. in laterodorsal view; E. dorsal view, F. laterointernal view. G–I. S. (H.) estevezi, H. dorsal view, I. ventral view. J–M. S. (H.) dalmati, J. lateral view, K. dorsal view, L. frontal view. M. ventral view. N–O. S. (H.) juarezi, N. lateral view, O. dorsal view. (A, B–E, G–O same scale).