ETHIOPIAN N AS UTITE RMITIN AE 



97 



T. geminatus (Wasmann) has previously been recorded as West African in distri- 

 bution (Snyder, 1949). The amalgamation of the species listed in the synonymy, 

 and much new material, has made it clear that it extends from the extreme west coast 

 of Africa, across to the foothills of the Ethiopian Massif, in the Guinean, Sudan, and 

 Sahel savannah-woodland vegetation zones (Keay et al., 1959, types 8, 16, 17, 20, 

 and 25). It is, in fact, the most abundant species in these areas, where it builds a 

 small mound from a few inches to two or three feet in diameter and height. The 

 biology of this species has been described in detail under its better-known synonym, 

 T. ebenerianus Sjostedt, in earlier papers (Sands, 1961, 1961a, 1963). 



Trinervitermes gratiosus (Sjostedt) 

 (Text-figs. 192, 235, 236, 250, 251, 276-281; Map 22) 



CONGO, Luluabourg. 

 Congo, Luluabourg. 



Entermes (Trinervitermes) gratiosus Sjostedt, 1924 : 42. Type locality 

 Eutermes (Trinervitermes) carbo Sjostedt, 1924 : 42. Type locality : 



syn. n. 

 Trinervitermes gratiosus (Sjostedt) Sjostedt, 1926 : 349. 

 Trinervitermes carbo (Sjostedt) Sjostedt, 1926 : 351. 



Imago. Head capsule, central part of frons and vertex pale brown to brown ; vertex with 

 three diverging yellow-brown streaks, middle one dilated terminally immediately behind fon- 

 tanelle ; postclypeus, labrum, anterior margin of frons behind postclypeus, around antennal 

 socket, and a triangular area behind eye paler, yellow brown. Antennae yellow-brown. Pro- 

 notum yellow, meso- and metanota yellow with posterior margins yellow-brown, other thoracic 

 sclerites pale yellow, legs yellow, bases of tibiae shaded darker, yellow-brown. Abdominal 

 tergites yellow-brown ; sternites yellow, yellow-brown round stigmata. Wings, membrane 

 translucent pale yellow-brown, subcosta yellow, and radius sector yellow, partially outlined 

 yellow-brown, rest of venation narrowly yellow-brown. 



Posterior margin of head behind eyes much less than semi-circular, slightly sinuate immed- 

 iately behind eyes ; fontanelle distinct, pale Y- or inverted A-shaped, lateral arms sometimes 

 somewhat dilated terminally ; eyes oval, prominent in proportion to own width, and medium 

 sized relative to head width, W/E index 2-8-3-1 ; ocelli medium sized, separated from eyes by 

 one-fifth to two-fifths own diameter ; postclypeus inflated, width 2-0-2-3 times length, anterior 

 margin slightly concave, posterior convex, rounded ; molar plate of right mandible with 8-9 

 ridges ; antennae, among eleven specimens examined, four had 15 segments, five 16, and two 17, 

 proportions of basal segments variable. 



Pale coloured " scent " gland on anterior margin of fifth abdominal sternite of $ large, 

 1 -15mm. wide, o-38mm. long ; cerci of $ shorter than or equal to width across base, conical. 



Pilosity of vertex fine, silky, sparse, and of uneven length, not forming a " pelt " or " mat ", 

 head capsule appears more shining than in many species. 



Measurements (11 specimens from 5 localities) in millimetres. 



Range Mean 



1-80-1-96 . . 1 89 



0-58-0-68 . . 064 



0-20-0-22 X 0-23-0-29 . . 0-21 X 0-27 



0-04-0-08 . . 0-06 



1-65-1-85 . . 1-79 



IOO-II8 . . I-I2 



2-32-2-50 . . 2-36 



17-30-23-20 . . 2079 



Head width across eyes 

 Greatest diameter of eye 

 Ocellus 

 Ocellus to eye 

 Width of pronotum 

 Length of pronotum 

 Length of hind tibia 

 Length of fore wing 



