Polyrhachis monista Santschi

Type location Congo (Santschi, 1910c: 398, illustrated, queen; Santschi, 1914d: 384, illustrated, worker; Bolton, 1973b: 343, illustrated, alitrunk and petiole only), no location. .

Santschi's (1910c) description is at , and his description of the worker (1914d) is at . Bolton's modern description (1973b) is at .

Nigeria specimen (Taylor, 1978: 21). WORKER. TL 5.5-6.4 mm, HL 1.27-1.52, HW 1.22-1.41, SL 1.40-1.59, PW 0.96-1.04
Coarse erect, pale hairs on all dorsal surfaces and pubescence generally sparse or absent. Unique development of the alitrunk, which is not marginate and the dorsal surfaces of the pronotum and propodeum rounded evenly into the sides. Both pronotum and propodeum armed with a pair of thick spines. The pronotum is separated from the mesonotum by a deep broad groove, and the mesonotum and propodeum are similarly separated with the latter groove angled forwards to meet the former. The petiole has four well-developed spines, the lateral pair being longer than the dorsal pair. The anterodorsal border of the first gastral segment has a sharp margin separating the concave anterior face from the convex dorsal surface.

Arboreal, with nests usually being a mixture of silk and vegetable particles, often between a pair of leaves. In Nigeria, I found it on a native tree at CRIN. Bolton (1973b) had earlier collections as being at Ibadan (J. Cloudsley-Thompson; R.H. Booker). Earlier from CRIN, perhaps on 5-10% of cocoa in pkd collections from two cocoa blocks, W13/2 and W18/1 (Booker, 1968).

Wheeler (1922) listed it from Ghana (at Aburi, by F. Silvestri, the collection in Santschi, 1914d) and it was collected from cocoa at Kade by Majer (1975).

Bolton's (1973b) distribution includes Ghana (probably collected by F. Silvestri, see Bolton, 1995), Zaïre and Uganda but without any details.