Eurytenes dichromus Walker & Wharton

Walker, Andrea K. & Wharton, Robert A., 2011, A review of New World Eurytenes s. str. (Hymenoptera, Braconidae, Opiinae), Journal of Hymenoptera Research 20, pp. 23-46 : 32-34

Eurytenes dichromus Walker & Wharton sp. n. Figs 2715-21303233

Holotype

♀ (TAMU): [USA:] TEXAS: Brazos Co. College Station Lick Creek Park 28. iv– 11.v.2001 R. Wharton [five lines on a single label].

Paratypes

(TAMU, USNM): 5 ♀, same data as holotype; 5 ♀, same data except 11-21.v.2001; 2 ♀, same data except 15-28.iv.2001; 1 ♀, same data except 1-11.vi.2001; 1 ♀, same data except 6-16.iv.2007, M. Cameron & A. Colvin; 1 ♀, same data except 19.iv-12.v.2009, J. B. Woolley; 1 ♀, Texas, Travis Co., Austin, Longhollow, 10-23.iv.1993. R. Wharton; 1 ♀, Texas, Walker Co., Huntsville, 2.iv.2006, R. Wharton. Additional specimens, not paratypes (TAMU): 2 ♀, Florida, Alachua Co., Hague Dairy, 29 47.311'N, 82 24.880'W, 28.iii.2007, J. Sivinski; 1 ♀, same data except 29 47.328'N, 82 24.969'W, 29.iii.2007; 1 ♀, Texas, Anderson Co., 10 mi SW Elkhart, 5-6.vi.1976, H. R. Burke.

Diagnosis.

This species is most readily recognized by its broader, bicolored petiole and bicolored, ventrally truncate clypeus. Based on the shape and color pattern of the petiole, as well as the shape of the clypeus, Eurytenes dichromus is most similar to Eurytenes microsomus , sp. n. The propodeum is nearly always more heavily sculptured in Eurytenes dichromus than in Eurytenes microsomus and usually slightly more rugulose posterior-laterally than in Eurytenes abnormis .

Description

(♀). Length of body: 2.4-2.7 mm (m=2.6), length of fore wing 2.9-3.1 mm (m=3.0).

Head. 31-35 flagellomeres; first flagellomere length 2.6-3.3 × width (m=3.0), fifteenth flagellomere length 2.0-2.3 × width (m=2.2), fifth from last flagellomere, length 1.7-2.4 × width (m=2.0). Face 1.6-1.9 (m=1.7) × wider than high. Clypeus semi-ellipsoidal in shape, with ventral margin truncate or nearly so, 2.2-2.8 (m=2.4) × wider than high; 1.3-1.7 (m=1.45) × wider than distance between clypeus and eye. Mandible distinctly expanded over basal 0.3, with flange-like ventral carina. Gena relatively narrow (Fig. 15). Occipital carina extending about 0.3-0.4 × distance from eye to nearest lateral ocellus.

Mesosoma.Posterior-ventral margin of lateral pronotum crenulate for most of length. Precoxal sulcus narrowly crenulate anteriorly, sculptured area broadening posteriorly, usually weakly impressed anteriorly, often extending very close to anterior margin of mesopleuron; precoxal sulcus approximately 45 degrees, inclined more vertically than in Eurytenes abnormis. Notaulus distinctly impressed over anterior third of mesoscutal disc, crenulate over anterior 0.2-0.3; with dense cluster of short setae at rugulose base of anterior declivity extending ventrally to cover most of anterior declivity; with widely spaced line of 3-5 longer setae extending posteriorly towards but not usually reaching cluster of scattered setae around midpit as in Fig. 30. Propodeum with median carina present anteriorly, bifurcating near basal 0.3 to form five-sided median areola over posterior 0.6-0.7, surface extensively rugose laterally and posterior-medially (Figs 32, 33), partly obscuring areola, posterior-lateral fields often completely rugose.

Wings. Fore wing r-m pigmented basally, less commonly over anterior 0.5, otherwise unpigmented, largely tubular, with lateral boundaries usually distinct for most of length; m-cu usually postfurcal, entering base of second submarginal cell, less commonly interstitial; 3M distinctly pigmented, nearly tubular in basal third, gradually weakening and becoming depigmented distally. Hind wing m-cu usually poorly developed, varying from very weakly to distinctly impressed.

Legs. Hind tibia 7.5-9.1 (m=8.25) × longer than maximum width.

Metasoma. Petiole 1.45-1.8 (m=1.6) × longer than apical width. Female ovipositor short, but distinctly protruding, about 0.8 × length of mesosoma. Ovipositor sheath about 0.4 × length of mesosoma.

Color. Head and mesosoma black, with small red-brown spot adjacent eye dorsal-medially near ocelli, face at base of antennae also usually red-brown. Scape and pedicel yellow, flagellomeres dark brown; mandible butterscotch with distal tip infuscated; clypeus infuscated, dark brown dorsally, butterscotch ventrally; palps and tegula yellow. Petiole dark brown dorsally, posterior fifth and ventral-lateral region usually yellow. T2+3 butterscotch medially; T2 and T3 each with a medium brown lateral splotch; T4 and successive tergites each with dark brown transverse banding anteriorly fading to butterscotch posteriorly. Hind tibia pale yellow to whitish over about basal 0.15, remainder infuscated to medium brown, tarsus completely medium brown, legs otherwise yellow to nearly white, with femur and trochantellus often (though not in holotype) darker yellow than coxa and trochanter. Ovipositor sheath dark brown; ovipositor light brown. Wings hyaline.

Male and Host.

Unknown.

Distribution.

Known only from central Texas.

Etymology.

The name dichromus is derived from Greek: di, two; chromus, color. The name refers to the color of the clypeus.

Comments.

Fischer (1965) noted a considerable range in body size for Eurytenes abnormis . Body size is affected by host size (e. g. Wharton 1983), and the consistent difference in body size between Eurytenes dichromus and Eurytenes microsomus , sp. n. suggests different patterns of host utilization for these two nearly identical species. The non-paratypes are all relatively poorly preserved, obscuring the true color pattern, but indicate a fairly broad geographical range for this species. This species is thus far known only from females.