Mesostruma bella

Identification
This species is most similar to Mesostruma browni but differs as follows:
 * 1. The posterior margin of the head is more deeply concave and its lateral corners are more sharply angular.  In M. browni this margin is shallowly concave and the lateral corners are broadly rounded.
 * 2. The sculpturing on the metapleural gland bulb consists of small, closely spaced punctures, sometimes with up to several weak rugae.  In M. browni the sculpturing on the bulb consists of large fovae and irregular rugae.
 * 3. The upper margins of the propodeal lamellae, in lateral view, are convex and the posterior margins have a very weak concavity just below the dorsal angles.  In M. browni the upper margins of the lamellae are sinuate (convex basally, concave near the angle) and the posterior margin have a distinct concavity just below the dorsal angles.
 * 4. Mesostruma bella averages larger (HW 0.72 mm to 0.84 mm) than M. browni (HW 0.62 mm to 0.75 mm).

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  bella. Mesostruma bella Shattuck, in Bolton, 2000: 48 (w.) AUSTRALIA.

Description
HOLOTYPE WORKER. TL 3.9, HL 0.90, HW 0.84, CI 93, ML 0.36, MI 40, SL 0.48, SI 57, PW 0.58, AL 1.00. Head relatively broad (CI > 88), its posterior margin relatively deeply concave; eyes relatively large (maximum eye diameter/head length >= 0.19). Pronotum relatively wide (about 0.66-0.69 times mesosoma length), in dorsal view its anterolateral corners rounded. Dorsum of mesosoma with scattered, shallow foveolate punctures which are spaced more than their width apart, the area between the punctures smooth and lacking sculpturing. Propodeal lamellae with the dorsal margins convex, the posterior margins weakly concave, the angles between these margins acute, less than 90 degrees. Sculpturing on the metapleural gland bulb consisting of small, closely spaced punctures, occasionally with up to several weak rugae. Postpetiole expanded laterally and wing-like. First gastral segment immediately posterior of the postpetiole with short, irregularly spaced rugae. Body relatively large (maximum head width > 0.72mm), colour dark red-brown with moderate infuscation.



Type Material
Holotype worker, New South Wales, junction of Braidwood and Caption’s Flat Roads, near Queanbeyan, 8 July 1971, from grass tussocks (S. Misco). Paratypes, 2 workers, same data as holotype.