Strumigenys beebei group

Strumigenys beebei group Bolton (2000)

Worker Diagnosis
Mandibles in full-face view and at full closure short; masticatory margins engage throughout their length. Teeth lengthening distally so that the cuticular margins from which the rows of teeth arise are strongly divergent anteriorly and form a marked inverted V-shape. In profile masticatory margin of mandible arched down-curved distal of the clypeus. In ventral view outer margin of mandible with a strongly inflected prebasal angle. MI 9-11.

Dentition. Basal tooth to tooth 5 consist of stout somewhat recurved teeth that gradually increase in length from the basal; distal to this with two smaller teeth, giving a total dental count of 7.

Basal lamella of mandible high, subrectangular, broadly truncated apically and with a steeply oblique anterior margin from which the basal one or two teeth arise; anterior margin of lamella visible in full-face view with mandibles fully closed.

Labrum broadly bilobate, the lobes flat and rounded apically. Lateral margins of labrum, in dorsal view with mandibles open, only very slightly divergent from base to apex.

Clypeus with anterior margin broadly and evenly concave. Lateral margins strongly expanded, the margins convex and concealing the basal portions of the outer margins of the mandibles; the latter intersecting the anterior clypeal margin at its anterolateral angles.

Clypeal dorsum only with scattered minute appressed pubescence, the margins without projecting hairs of any form. Clypeal suture very indistinct, almost effaced.

Upper scrobe margins behind level of antennal insertions shallowly concave in full-face view. Maximum width of head across occipital lobes only fractionally greater than width across clypeus.

Preocular carina not visible in full-face view, overhung and concealed by the lateral expansion of the frontal lobe.

Ventrolateral margin of head distinctly marginate in front of the eye, the margination almost straight, only extremely feebly concave. Postbuccal impression broad and concave between the ventrolateral marginations, but the latter not involved in the impression.

Cuticle of side of head within the antennal scrobe smooth and highly polished.

Scape short, SI 57-62, slender and somewhat dorsoventrally flattened.

Leading edge of scape without hairs of any form.

Head in profile subtruncate anteriorly; dorsal outline of clypeus and anterior part of frons angled abruptly downward with respect to remainder of cephalic dorsal outline.

Pronotum not marginate dorsolaterally.

Propodeum armed with a pair of elongate spines that are broad basally and rapidly taper to a slender acute apex.

Spongiform appendages fully developed on waist segments: petiole with a ventral curtain and node with lateral lobes; postpetiole with large lateral and ventral lobes; base of first gastral sternite with a spongiform pad.

Pilosity. Pronotal humeral hair present, extremely long and flagellate. Head without standing or laterally projecting hairs of any form. Mesonotum with a single pair of extremely long flagellate hairs that curve toward the head. Dorsal surfaces of petiole, postpetiole and first gastral tergite with fine flagellate hairs. Middle and hind tibiae with short fine hairs that are all decumbent to appressed.