THE SOLDIERLESS TERMITES OF AFRICA 83 



Left mandible, third marginal to molar 





(Lm) 



008 



Right mandible, apical to first marginal 





(Ra) 



007-009 



Right mandible, first to second mar- 





ginal (Ri) 



012 



Right mandible, second marginal to 





molar (R m ) ..... 



006 



Mesonotum width (M) 



0-19-0-23 



Metanotum width (N) 



0-22-0-25 



Worker. Head capsule pale yellow, pilosity yellow, fairly sparse. Postclypeus moderately 

 inflated, Pcl/W, 027, Pcl/Rj, 185; apical teeth of mandibles short, La/Li, 051, R A /Ri. o-6i ; 

 subsidiary marginal tooth of left mandible just clear of molar prominence in surface view, 

 complex ratio La/Li. L m , 10-32; first marginal tooth of right mandible distinctly behind line of 

 apical to second, its anterior margin approximately half length of second, R A /Ri.R m . 12-71. 

 Fore tibia weakly inflated, Ti/T w , 402, third apical spur distinct, slightly shorter than other 

 two. Mesenteric junction with proctodeum nearly diagonal, midway through malpighian 

 knot; enteric valve seating ventrolateral in unopened abdomen, weakly three-lobed, third 

 lobe smaller than outer two, sessile on second pouch of proctodeum or with very short neck; 

 membranous wall of valve beyond cushions with sparse minute spicules. 



Measurements (one specimen) in millimetres: 



Head width (VV) .... 0-70 



Fore tibia width (T w ) . . .0-12 



Fore tibia length (Ti) .... 0-46 

 Postclypeus length (Pel) . . .0-19 



Left mandible, apical to first marginal (L A ) 0-06 



Left mandible, first to third marginal (Li) . 0-12 

 Left mandible, third marginal to molar 



(Lm) 005 



Right mandible, apical to first marginal 



(Ra) 006 



Right mandible, first to second marginal 



(Ri) 010 



Right mandible, second marginal to molar 



(Rm) 005 



Although first in alphabetic order in Group III, A. acholus is an aberrant species 

 easily distinguished from all others in the imago by the widely sexually dimorphic 

 fontanelle which is extremely conspicuous, particularly in the $. In the worker 

 caste the much reduced first marginal tooth characterizes Group III and A. acholus 

 is distinguished from A. brevior, A. obstructus and A. quietus in having the enteric 

 valve seating ventrolateral in the unopened abdomen, together with minor features 

 given in the key. The worker abdomen does not appear to be dehiscent. 



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

 Democratic Republic of Congo: Mbamba (Bas Congo), 6.x. 1966 (C. Nkakala) 

 in Mus£e Royal de l'Afrique Centrale, Tervuren. (Paratypes from type-colony, 

 $ and <J imagos and workers, in British Museum (Natural History) and at University 

 of Lovanium, Kinshasa.) 



There is no biological information about the single nest-series. 



