ETHIOPIAN NASUTITERMITINAE 79 



Key to Species 

 Imagos 



Ocellus separated from compound eye by more than two-fifths of own width (i.e. 



shortest diameter) ........... 2 



Ocellus separated from compound eye by two-fifths of own width or less . . 4 



Frons usually with two shallow diverging depressions in front of fontanelle. Smaller, 

 head width across eyes (VV), 1-45-1-83 ; greatest diameter of compound eye (E), 

 0-43-0-58 ; hind tibia length (T 3 ), 1-81-2-24 ...... 3 



Frons without such depressions. Larger, W, 1-61-2-03 • E, 0-42-0-56 ; T 3 , 



2-02-2-47 .......... trinervoides (p. 132) 



Fontanelle with short lateral arms. Compound eye larger in proportion to head 

 width, W/E index 3-0-3-5. Ocellus separated from eye by up to half own width. 

 Female cerci longer than basal breadth ..... rapulum (p. no) 



Fontanelle lateral arms long, reaching almost halfway to ocelli. \Y/E index 3-5-39. 

 Ocellus separated from eye by half own width or more. Female cerci as long as 

 basal breadth ......... saudiensis (p. 120) 



Antennae 15-16 segmented .......... 5 



Antennae 17-18 segmented .......... 14 



Scent gland on fifth abdominal sternite of female large, over i-omm. wide, over 



0-25111111. long ; that of male smaller, approximately as female of other species . 6 



Scent gland on fifth abdominal sternite of female smaller, under o-tjmm. wide, under 



0-23111111. long ; that of male, smaller than female ...... 7 



Molar plate of right mandible with 5-6 ridges, posterior ridges obsolescent, some- 

 times unevenly shaped. Smaller, W, 1-55-1-82 ; E, 0-47-0-59 ; T 3 , 1-98-2-43. 

 Antennae 15 segmented, sometimes with a basal segment partially subdivided 



bettonianus (p. 84) 



Molar plate of right mandible with 8 <) ridges Larger, W, 1 No- 1 06 ; E, 05S 

 o-6o ; T 3 , 2-32-2-50. Antennae, 63% of specimens 16 or more segmented 



gratiosus (p. 97) 



Antennae 16 segmented or if 15, with one or more basal segments partially sub- 

 divided ............. 8 



Antennae 15 segmented ........... 10 



Vertex with three diverging pale streaks or patches on darker ground colour. 



W. Africa, N. Congo, N. Uganda, Sudan .... togoensis (p. 122) 



Vertex without such streaks, though sometimes clouded or patched with paler colour 



in one area. East Africa, S. Congo, Central and S. Africa .... 9 



Frons usually with two shallow diverging depressions anterior to fontanelle. Post- 



clypeus, width 1-9-2-2 times length ..... rapulum (p. no) 



Frons without such depressions, though sometimes with single median shallow- 

 depression. Postclypeus, width 2-2-2-5 times length • • rhodesiensis (p. 114) 



Compound eye, greatest diameter under 0-50 . . . . . . . n 



Compound eye, greatest diameter 0-50 or more ...... 12 



Frons usually with two shallow diverging depressions in front of fontanelle ; fon- 

 tanelle short broad Y-shaped or U-shaped, margins often indistinct. Postclypeus, 

 width 1 -9-2 -2 times length. Larger, \V, 1 -45-1 -83 ; E, 0-47-0-58 ; T 3 , 1-81-2-20 



rapulum (p. no) 



Frons without paired depressions, sometimes with single median shallow depression 

 in front of fontanelle, sometimes fiat ; fontanelle slender Y-shaped, sometimes 

 with dark patch at posterior end. Postclypeus, width 2-1-2-5 times length. 

 Smaller W, 1-35-1-58 ; E, 0-43-0-50 (one only recorded) ; T 3 , 1-63-1-99 



dispar (p. 87) 



