Eurytenes microsomus Walker & Wharton, 2011

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 1 3 34 35

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.

Figures

Figures 1 - 3. 1 Eurytenes microsomus sp. n., face, bars = clypeal measurements 2 Eurytenes dichromus sp. n., petiole, lateral view, bar = length measurement 3 Eurytenes microsomus, lateral view, arrow = precoxal sulcus, bar = mesosomal length.

Figures 32 - 35. Propodeal sculpture patterns. 32 - 33 Eurytenes dichromus sp. n. 34 - 35 Eurytenes microsomus sp. n.