46 W. A. SANDS 



termes probably closely resembles the ancestral forms of the group. This is why 

 Acidnotermes is placed first in the systematic order of arrangement of this paper. 

 The only external characters of worker or imago that I would regard as likely to be 

 specialized are the swollen fore tibia of the former and the narrow meso- and 

 metanota of the latter. The insertion of the malpighian tubules at the mid-point 

 of the mesenteron instead of nearer to the junction with the proctodeum probably 

 also represents a specialization carried a little further in this genus than in any 

 other. 



Acidnotermes praus sp. n. 



(Text-figs 32-42; PI. 1, fig. 1) 



Imago. Head capsule brown, sepia-brown above ocelli, dark areas sometimes extending 

 as tapering streaks converging to fontanelle; fontanelle minute, circular to elongate oval, 

 slightly raised on small bump, pale yellow-brown; medial spot circular or short oval, smaller 

 than fontanelle, also raised on small bump, brown; postclypeus pale brown, labrum pale yellow; 

 frontal marks very indistinct pale brown; antennae pale yellow-brown. Pronotum, meso- and 

 metanota pale brown ; legs, femora and tibiae pale yellow-brown, tarsi pale yellow. Abdominal 

 tergites pale yellow-brown, dorsal stigmata paler, yellow; sternites, very pale yellow-brown 

 laterally, yellow-white in middle, ventral stigmata darker, pale yellow-brown, cerci yellow- 

 white. 



Posterior margin of head capsule evenly rounded except immediately behind compound 

 eyes, ocelli proportionately rather large, separated from eyes by less than half own least dia- 

 meter, nearly touching in some specimens; postclypeus moderately inflated, Pcl/W, 0-25-0-30 

 posterior margin rounded, somewhat more arched in middle, median suture distinct. Pilosity 

 of head capsule very dense, pale, slightly uneven in length, scarcely forming a pelt. 



Measurements (10 specimens from five localities) in millimetres. 



Range Mean ± S.D. 



Head width across eyes (W) 0-57-0-66 0596 ± 0-030 

 Ocellus (O w x Oi) . . 005-006 x 0-07-0-09 0058 i 0-004 X 0-077 ± 0006 



Ocellus to eye (O-E) . 0-01-0-02 0-014 ± 0-005 



Postclypeus length (Pel) . 0-15-0-18 0160 ± 0-009 



Antennal article III . . 0-01-0-02 0015 ± 0-003 



Antennal article IV . — 0022 ± 0002 



Antennal article V . . 0-02-0-03 0023 i 0-002 



Left mandible, apical to 



first marginal (La) ■ 0-04-0-05 °°45 ± 0-002 



Left mandible, first to third 



marginal (Li) . . 0-08-0-09 0085 ^ 0-004 

 Left mandible, third mar- 

 ginal to molar (L m ) . 0-04-0-05 °°45 ± 0-003 

 Right mandible, apical to 



first marginal (Ra) • 004-0-05 0-047 ± 0-002 



Right mandible, first to 



second marginal (Ri) . 0-06-0-08 0-071 ± 0005 

 Right mandible, second 



marginal to molar (R m ) • 0-04-0-05 0-046 ± 0-003 



Mesonotum width (M) . 0-10-0-15 0-128 i 0-002 



Metanotum width (N) . 0-10-0-14 0121 ± 0-002 



