162 W. A. SANDS 



- Compound eyes and ocelli smaller, W/E, 3-60-4-16, O w /0-E, 0-71-1-80 (i.e. separated 



by more than half least diameter of ocellus) ....... 3 



2 Larger, W, 1-16-1-24. Postclypeus moderately inflated, Pcl/W, 0-27-0-28 



rastratus (p. 171) 



- Smaller, W, 0-98-1-04. Postclypeus scarcely inflated, Pcl/W, 0-23 retifaciens (p. 174) 



3 Right mandible with anterior edge of first marginal tooth longer than that of second . 4 



- Right mandible with anterior edge of first marginal tooth equal to or shorter than 



that of second ............ 6 



4 Postclypeus strongly inflated, Pcl/W, 0-29. Fore tibia with third apical spur vestigial, 



nearly obsolete. Ocellus separated from compound eye by distinctly more than 



own least diameter, O w /0-E, 0-71 ...... tranquillus (p. 181) 



- Postclypeus less inflated, Pcl/W, 0-23-0-26. Fore tibia with third apical spur 



smaller but not vestigial. Ocellus separated from compound eye by less than 



own least diameter or slightly more, O w /0-E, 0-90-1-31 ..... 5 



5 Fontanelle short oval, coloured as head capsule. Pilosity of head capsule forming a 



somewhat rough pelt with uneven emergent setae. (Distribution, E. Africa) 



pectinatus (p. 168) 



- Fontanelle irregularly rounded triangular, paler than head. Pilosity of head capsule 



forming a short, fine, even pelt with emergent setae. (Distribution, W. Africa) 



sentosus (p. 176) 



6 Smaller, W, 0-90-1-01. Ocelli slightly closer to compound eyes, O w /0-E, 1-19-1-80 



ctenopher (p. 163) 



- Larger, W, 1-10-1-23. Ocelli further from compound eyes, O w /0-E, 0-82-1-13 • 7 



7 Apical teeth of mandibles longer, La/Li, o-66, Ra/Ri, i-oi. Mesonotum narrower at 



constriction, M/W, 0-26. ...... . spinulatus (p. 179) 



- Apical teeth of mandibles shorter, La/Li, 0-50-0-60, R A /Ri, 0-70-0-84. Mesonotum 



wider at constriction, M/W, 0-28-0-34 ..... muricatus (p. 165) 



Workers 



1 Enteric valve cushion in position 1 sclerotized only on distal half, only about one- 



quarter of total length of cushion protruding beyond tips of spines of other cushions; 

 these spines stout and abruptly tapered at tips, not hooked (PI. 4, fig. 5). Larger, 

 W, i-io. Enteric valve seating with distinct neck . . . tranquillus (p. 181) 



- Enteric valve cushion in position 1 sclerotized throughout its length, of which about 



half protrudes beyond tips of spines of other cushions; these spines more slender, 

 more finely tapered at tips, sometimes hooked. Smaller, W, 0-75-0-99. Enteric 

 valve seating sessile or nearly so ........ . 2 



2 Left mandible with proximal end of subsidiary marginal tooth level with edge of 



molar prominence in surface view. Enteric valve cushions in positions 2, 3 and 4 

 with extremely long fine slender spines, each with a completely recurved hook 

 at the tip, capable of engagement with other spines to form a criss-crossed network 

 (PL 6, figs 6-8) ........ . retifaciens (p. 174) 



- Left mandible with proximal end of subsidiary marginal tooth clear of molar pro- 



minence in surface view. Enteric valve cushions in positions 2, 3 and 4 with 

 shorter, less fine spines, if hooked, tips not fully recurved, incapable of engagement 

 with other spines as above .......... 3 



3 Smaller, W, 0-75-0-85. Apical teeth of mandibles shorter, La/Li, 0-45-0-58, R A /Ri, 



0-59-0-74. Fore tibia slightly thicker, Ti/T w , 4-72-5-10 ..... 4 



- Larger, W, 0-91-0-99. Apical teeth of mandibles longer, La/Li, 0-64-0-74, Ra/Ri, 



o-86-i-oi. Fore tibia thinner in most species, Ti/T w , 5-05-5-90 (only one under 



5-2o) .... 5 



4 Postclypeus more inflated, Pcl/W, 0-26-0-28. Enteric valve cushion 1 with dilated 



outer end inflated in the middle and armed with two rows of prominent spines, 



