86 W. A. SANDS 



Right mandible, apical to 



first marginal (R A ) • 006-010 0082 i 0-009 



Right mandible, first to 



second marginal (Ri) . 0-09-0-15 0122 ± 0-013 



Right mandible, second 



marginal to molar (R m ) . 006-009 0073 i 0-008 



Mesonotum width (M) . 0-24-0-35 0290 ± 0-030 



Metanotum width (N) . 0-25-0-35 0-302 ± 0-027 



Worker. Head capsule yellow-white, pilosity pale yellow, sparse and inconspicuous. Post- 

 clypeus moderately to strongly inflated, Pcl/W, 0-29-0-33, Pcl/R|, 2-59-3-08; apical teeth of 

 mandibles short, La/Li, 0-43-0-54, Ra/Ri, 0-57-0-76; subsidiary marginal tooth of left mandible 

 just clear of molar prominence in surface view, complex ratio La/Li. Lm, 9-38-12-41; first 

 marginal of right mandible distinctly behind line of apical to second, its anterior margin ap- 

 proximately half length of second, Ra/RiRiti. 11-26-14-10. Fore tibia scarcely inflated, 

 Ti/T w , 4-32-5-00, third apical spur distinct, one-third to one-half length of other two. Mesen- 

 teric junction with proctodeum diagonal or slightly longer, to right of malpighian knot; enteric 

 valve seating dorsolateral in unopened abdomen, weakly two-lobed, sometimes vestige of 

 third lobe, sessile on second pouch of proctodeum ; cushions of enteric valve in positions 3 and 4 

 with a few minute spines on proximal third, membranous wall of valve beyond cushions with 

 sparse minute spicules. 



Measurements (12 specimens from 12 localities) in millimetres. 



Head width (W) .... 



Fore tibia width (T w ) . 



Fore tibia length (Ti) .... 



Postclypeus length (Pel) 



Left mandible, apical to first marginal (La) 



Left mandible, first to third marginal (Li) 



Left mandible, third marginal to molar (L m ) 



Right mandible, apical to first marginal (R A ) 



Right mandible, first to second marginal (Rj) 



Right mandible, second marginal to molar (R 



Range Mean ± S.D. 



0-75-0-93 0846 ± 0045 



0-12-0-14 °' I 34 ± 0007 



0-51-0-66 0622 ± 0041 



0-23-0-29 0262 ± 0015 



006-009 °'°74 db 0009 



011-0-15 OI 33 ± 0012 



004-006 0050 ± 0-004 



0-06-0-08 0-070 ± 0008 



008-01 1 0094 i ooio 



0-05-0-07 0060 ± 0006 



The large number of nest-series of this species available has permitted some study 

 of the variation to be made, as indicated in the description above. This has led 

 to its having been described from different parts of its range under two synonyms. 

 It has been confused with other species in the imago, particularly Alyscotermes 

 kilimandjaricus (Sjostedt) with which it is partly sympatric; however the different 

 proportions of the marginal teeth of the right mandible are diagnostic here. 

 A. brevior most closely resembles A. quietus, the two being very hard to separate. 

 Such differences as there are, are a matter of degree. In A. brevior the imago 

 head pilosity is less even, the postclypeus has a more definite median suture, and the 

 transverse sutures of meso- and metanota are more developed. In general also the 

 ocellus is further from the compound eye, but there is an overlap in this character. 

 In the worker caste there is more distinction in that the reduction of the right 

 first marginal tooth has proceeded further in A . quietus, and its enteric valve cushions 

 are completely unarmed. A. obstructus, the other Group III species is easily 

 separated, having the ocelli nearly touching the eyes, in the worker by the necked 

 enteric valve, and in both castes by its small size. The abdomen of the worker 



