Eurytenes microsomus 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 : 34-35

Eurytenes microsomus Walker & Wharton sp. n. Figs 133435

Holotype

♀ (TAMU): [USA:] TX: San Patricio Co. Welder Wildlife Refuge March 23, 1996 R. Wharton [five lines on a single label].

Paratypes

(TAMU): 3 ♀, 3 ♂, same data as holotype; 1 ♂, Texas, Travis Co., Austin, 20.ix.1986, R. Wharton; 1 ♀, same data except 29.iv.1989; 1 ♀, Travis Co., vic. Long Hollow Ck. 30°27'43", -97°52'19", 26.iii.1994, on Quercus buckleyi , M. Quinn, E. Riley, R. Wharton.

Diagnosis.

This species is nearly identical to Eurytenes dichromus but Eurytenes dichromus is 1.25 × larger. The body is less heavily sculptured than in Eurytenes dichromus , there are fewer flagellomeres, and T2+3 tends to be paler in coloration.

Description

(♀). Length of body: 2.00-2.12 mm (m=2.08), length of fore wing 2.4-2.7 mm (m=2.5).

Head. 29-31 flagellomeres; first flagellomere length 2.3-3.6 × width (m=2.8), fifteenth flagellomere length 2.0-3.0 × width (m=2.3), fifth from last flagellomere length 2.0-2.8 × width (m=2.3). Face 1.4-1.7 (m=1.6) × wider than high. Clypeus more nearly semi-circular in shape, with ventral margin truncate, 2.0-2.5 (m=2.2) × wider than high; 1.5-1.9 (m=1.7) × wider than distance between clypeus and eye. Mandible distinctly expanded over basal 0.3, with flange-like ventral carina. Gena relatively narrow (Fig. 3). Occipital carina extending about 0.3-0.4 × distance from eye to nearest lateral ocellus.

Mesosoma. Posterior-ventral margin of lateral pronotum weakly crenulate, nearly smooth for most of length. Precoxal sulcus parallel-sided, narrowly crenulate, short, weakly impressed anteriorly, not extending close to anterior margin of mesopleuron; precoxal sulcus at 45 degree angle, inclined more vertically than in Eurytenes abnormis . Notaulus distinctly impressed over anterior third of mesoscutal disc, crenulate over anterior 0.2-0.3; with moderately dense cluster of short setae at rugulose base of anterior declivity extending ventrally to cover much of anterior declivity; with widely spaced line of 3-4 longer setae extending posteriorly towards but not reaching cluster of scattered setae around midpit (Fig. 3). Propodeum with median carina extending over anterior 0.3 before bifurcating to form five-sided areola over posterior 0.7. Surface smooth to weakly rugose laterally and posteriorly, carinae forming areola not obscured by sculpture, entirely visible, areola varying from smooth to weakly rugose (Figs 34, 35).

Wings.Fore wing r-m at most pigmented at extreme base, largely tubular (with lateral boundaries distinct) over anterior half; m-cu distinctly postfurcal; 3M distinctly pigmented in basal third, gradually weakening and becoming depigmented distally. Hind wing m-cu indistinct.

Legs. Hind tibia 7.5-8.7 (m=8.1) × longer than maximum width.

Metasoma. Petiole 1.6-1.8 (m=1.7) × longer than apical width. Female ovipositor short but distinctly protruding, about 0.9 × length of mesosoma. Ovipositor about 0.5 × length of mesosoma.

Color. Head and mesosoma dark reddish-brown as in Eurytenes abnormis , but with pale spot adjacent eye similar to though weaker than the spot in Eurytenes dichromus . Scape and pedical butterscotch, flagellomeres medium brown; clypeus butterscotch with slight infuscation dorsally. Palps, mandible, tegula, petiole, and ovipositor as in Eurytenes dichromus . Metasoma posteriad petiole patterned as in Eurytenes dichromus but T2+3 paler, whitish medially and T2 more lightly infuscate laterally. Legs about as in Eurytenes dichromus , with hind legs often a little paler. Ovipositor sheath dark red-brown. Wings hyaline.

Male.

Same as female except length of body 1.97-2.05 mm (m=2.01), length of fore wing 2.0-2.4 mm (m=2.3). Antenna with 24-28 flagellomeres; first flagellomere length 3.0-3.5 × width (m=3.4), fifteenth flagellomere length 2.4-3.0 × width (m=2.6), fifth from last flagellomere length 2.0-2.5 × width (m=2.4). Clypeus 1.3-2.3 (m=1.8) × wider than distance between clypeus and eye. Hind tibia 7.5-8.3 (m=7.9) × longer than maximum width. Petiole 2.0 × longer than apical width. Metasoma butterscotch dorsally with medium brown lateral banding on T2 and T3.

Host.

Unknown.

Distribution.

Central Texas.

Etymology.

The name microsomus is derived from Greek: micro, small; somus, body. The name refers to the smaller size of this species compared to other species of Eurytenes .

Comments.

Eurytenes microsomus and Eurytenes dichromus both occur in Austin, the westernmost locality for either species.