ioo W. A. SANDS 



Left mandible, third marginal to molar 



(Lm) 0-04 



Right mandible, apical to first marginal 



(Ra) 007 



Right mandible, first to second marginal 



(R,) 010 



Right mandible, second marginal to molar 



(R m ) 005 



This medium-sized species, as stated in the introduction to the genus, resembles 

 the Group I species. It differs from A. amicus in the proportionately longer post- 

 clypeus and shorter apical teeth of the mandibles. The very different proportions 

 of the mandibles, and in the worker, the gut characters, distinguish A. comis. 

 A. eumenus has narrower meso- and metanota and longer apical teeth. The other 

 species of Group I are not likely to be sympatric with A. impedians and are in any 

 case separable by similar characters. In Group II, A. hapalus is rather similar in 

 the imago though larger with wider meso- and metanota, and more inflated post- 

 clypeus. In the worker the apical teeth of the mandibles are longer and the 

 postclypeus much more inflated. A. mitis is likewise distinguished from A. im- 

 pedians except that the imago postclypeus is not more inflated. A. murcus from 

 the same locality as A. impedians is much larger with characteristic long head setae. 

 In Group III, A. brevior shows resemblances in some forms of the imago, though 

 usually much darker with pronounced transverse sutures on meso- and metanota, 

 and the proportions of mandibular teeth are different. The mandible characters 

 are accentuated in the worker, which also has an almost sessile enteric valve seating. 

 It is not known whether the worker abdomen is dehiscent in A. impedians. 



Holotype $ imago, paratype <$ imago and worker from type-colony, Zambia: 

 Ndola 30. i. 1957 (W. G. H. Coaton) in National Collection of Isoptera, No. TM4111, 

 Pretoria. 



No other material of this species is known and there is no information on its 

 biology. 



Astalotermes irrixosus sp. n. 



(Text-figs 206, 207, 212, 213 & 226-231; PI. 1, fig. 10) 



Imago. Head capsule dark chestnut-brown, very dark above ocelli; fontanelle oval, some- 

 what smaller than ocelli, slightly depressed, chestnut-brown; medial spot oval, flat, equal in 

 size to fontanelle or slightly smaller, colour as head; postclypeus brown, labrum yellow-brown; 

 frontal marks distinct chestnut-brown depressed crescents; antennae brown. Pronotum, 

 meso- and metanota, chestnut-brown, transverse dark sutures present; legs, femora yellow- 

 brown, tibiae paler, tarsi yellow. Abdominal tergites and dorsal stigmata, ventral stigmata 

 and lateral parts of sternites, brown; middle of sternites, and cerci, pale yellow-brown. 



Posterior margin of head capsule evenly rounded; ocelli rather small, separated from com- 

 pound eyes by two-thirds to five-sixths own least diameter; postclypeus moderately inflated, 

 Pcl/W, 0-26-0-27, Pc1/Ra, 2-92-3-I7, posterior margin evenly rounded, median suture distinct. 

 Apical teeth of mandibles short, La/Li, 0-52, Ra/Ri, 0-76-0-78; subsidiary marginal tooth of 

 left mandible separated from molar prominence by wide notch in surface view, complex ratio 

 La/Li. Lm, 5-2I-5-22; apical and marginal teeth of right mandible in line, anterior edge of first 



