212 W. A. SANDS 



Right mandible, apical to first mar- 

 ginal (R A ) ..... 006 



Right mandible, first to second mar- 

 ginal (Ri) ..... 008 



Right mandible, second marginal to 



molar (R m ) ..... 0-04 



A. improcinctus is one of the three smallest species of the genus, only A. nanus 

 being smaller, and this species has the first marginal tooth of the right mandible 

 shorter than the second in the imago, longer apical teeth in both castes, and an 

 armed enteric valve in the worker. A. polyscolus is about the same size, but in the 

 imago the fontanelle is larger and more conspicuous and the pilosity forms a pelt ; 

 the apical teeth are longer in both castes and the characteristic enteric valve is 

 easily recognized. The remaining species, A. improelatans, is larger and has less 

 constricted meso- and metanota in the imago ; the worker has a shorter mixed seg- 

 ment. The abdomen of the worker caste appears to be dehiscent in A. improcinctus. 



Holotype $ imago, paratype <$ and $ imagos, and workers from type-colony, 

 Nigeria : Northern Region, 20 miles from Yandev (near Gboko) on Makurdi Road, 

 25. ii. 1958 (W. A. Sands Coll., No. S.1928), in British Museum (Natural History). 



Other paratype material. Nigeria : Eastern Region, Nsukka, 20 miles from Enugu 

 on Oturkpo Road, 5.iii.i958 (W. A. Sands No. S.2040); Northern Region, Beli, 

 20 m. S.E. of Bakundi on Taraba River, 19. v. 1957 (W. A. Sands) also in BMNH. 

 Ivory Coast: Segue4a, 24. vi. 1964 (E. Ernst) in Swiss Tropical Institute, Basle. 



Anenteotermes improelatans sp. n. 



(Text-figs 544-547 & 550-565) 



Imago. Head capsule dark chestnut-brown, not appreciably darker above ocelli; fontanelle 

 vestigial, flat, minute oval spot, slightly paler than head; medial spot circular, flat, slightly 

 larger than fontanelle, coloured as head; postclypeus brown, labrum yellow-brown; frontal 

 marks semicircular, distinct, flat, brown; antennae pale brown. Pronotum, meso- and meta- 

 nota, sepia-brown, transverse sutures weak or absent; femora brown, tibiae yellow-brown 

 tarsi yellow. Abdominal tergites brown, dorsal stigmata sepia-brown, sternites pale brown 

 yellow-brown in middle, ventral stigmata brown; cerci yellow. 



Posterior margin of head capsule slightly undulating, not quite evenly rounded; ocelli 

 medium-sized, separated from compound eyes by up to half own least diameter; postclypeus 

 moderately inflated, Pcl/W, 0-27-0-31, posterior margin more or less evenly rounded, median 

 suture distinct. Apical teeth of mandibles short, La/Li, 0-54-0-59, Ra/Ri, 0-74-0-82; subsidiary 

 marginal tooth of left mandible separated from molar prominence by distinct notch in surface 

 view, complex ratio, LA/L].L m , 8-75-9-89; points of apical and marginal teeth of right mandible 

 in line, anterior edge of first marginal distinctly longer than that of second, complex ratio, 

 Ri/RA-Rm (note difference from ratio used in worker caste), 19-5-26-5. Pilosity of head capsule 

 relatively even, forming a pelt, but with some uneven emergent setae, brown. Meso- and 

 metanota wider at constrictions, M/W, 0-28-0-31. 



Measurements (six specimens from three nest series) in millimetres. 



Range Mean ± S.D. 



Head width across eyes (W) . 0-85-0-94 0-890 ± 0-041 



Ocellus (O w x Oi) . . . 0-07-0-08 x 0-09-0-10 0-074 ± 0-005 X 0096 ± 0007 



Ocellus to eye (O-E) . . 002-004 0029 ± 0-007 



