Polyrhachis semiinermis

A cryptic label reference stating the types were collected from a tree - "Site - empty cell in back of nest found in tree" (Donisthorpe 1941) - is all that is known about the biology of Polyrhachis semiinermis.

Identification
Kohout (2006): Characterised by widely rounded pronotal shoulders and a petiole that is virtually parallel-sided with the petiolar teeth reduced to mere denticles or completely lacking. Based on these characters, P. semiinermis is much more closely related to Polyrhachis danum from Borneo and Polyrhachis brevinoda from Australia than to Polyrhachis rastellata.

Distribution
Known only from type locality (see below).

This taxon was described from Philippines.

Abundance
Known only from types.

Castes
Known only from (type) workers.

Worker
Black, shining, articulations of scape, palpi, apex of trochanters and base of femur narrowly, extreme tip of antennae, spurs and claws reddish yellow. Clothed with a few outstanding pale yellow hairs, and very short, fine, sparse, decumbent little yellow hairs. The sculpturation consists of the usual fine reticulation and small puncuters.

The head is narrower and not so massive as in the typical form, more narrowed in front, not so broad and more abruptly rounded behind eyes; mandibles less massive. Thorax narrower, not so robust, more rounded in front and narrowed behind, shoulders quite round; promesonotal suture less deep and broad, no trace of mesoepinotal suture; epinotum entirely unarmed. The scale of the petiole is considerably narrower than in rastellata, the sides are straight, and there are no teeth to the external angles; two extremely small, short, pointed teeth are present in middle of upper border, another close together, the space between being slightly sinuate.

Long. 6 mm.

Type Material
Syntype workers from - as reported by Kohout (2006).

Type Locality Information
PHILIPPINES, Luzon, Baguio, 28-FEB-1920, col. A. Moore.