A cryptic label reference stating the types were collected from a tree "Site - empty cell in back of nest found in tree" (Donisthorpe 1941) and a second collection bears included this information label "Narra plantation with abaca understory". These records are all that is known about the biology of Polyrhachis semiinermis.
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. (Kohout 2006)
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Known only from a few collections.
Known only from workers.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- semiinermis. Polyrhachis (Cyrtomyrma) rastellata var. semiinermis Donisthorpe, 1941j: 209 (w.) PHILIPPINES. Raised to species: Kohout, 2006b: 91.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
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.
PHILIPPINES, Luzon, Baguio, 28-FEB-1920, col. A. Moore. Syntype workers from The Natural History Museum - as reported by Kohout (2006).
- Donisthorpe, H. 1941. Descriptions of new ants (Hym., Formicidae) from various localities. Annals and Magazine of Natural History (11)8:199-210. PDF
- Kohout, R. J. 2006. Review of Polyrhachis (Cyrtomyrma) Forel (Hymenoptera: Formicidae: Formicinae) of Australia, Borneo, New Guinea and the Solomon Islands with descriptions of new species. Memoirs of the Queensland Museum. 52:87-146. PDF