38 



W. A. SANDS 



Soldier. Head capsule yellow to ferruginous orange, nose orange to ferruginous. Pronotum 

 and antennae yellow to orange-yellow. Abdominal tergites and legs yellow, abdominal 

 sternites pale yellow. 



Head capsule in plan view short oval, tapering towards front, nose weakly conical. In 

 profile nearly straight, sometimes slightly concave or sinuate with weak hump at base of nose ; 

 nose shorter than rest of head capsule, measuring from hind margin of antennal socket, angle of 

 nose cone 12-15 degrees ; postmentum weakly convex ; antennae 12-14 segmented, usually 

 13, II and IV subequal, shorter than V, III longer than V. Head setae confined to four at nose 

 tip with shorter setae behind them, sometimes a bilaterally placed pair on vertex, and several 

 on front margin of postmentum. 



Abdominal tergites with very sparse minute setae, and a few fine short setae on posterior 

 margins of some or all segments ; sternites with scattered short setae, and longer setae towards 

 posterior margins. 



Measurements (22 specimens from 16 localities) in millimetres. 



Range Mean 



Head length to tip of nose 



1-33-1-70 



i-53 



Head width . 



0-63-1-05 



0-89 



Depth of head capsule . 



0-50-0-68 



060 



Width of pronotum 



0-42-0-64 



048 



Length of pronotum 



0-17-0-30 



0-2I 



Length of hind tibia 



Q-97-I-33 



i-o8 



Variation. The imago has not been found as variable as in some other species. In the 

 soldier caste it is common to find larger soldiers which have slightly different form and propor- 

 tions from the smaller members of the same colony, with distinct breaks in the range of variation. 

 These are probably derived from a different instar of development, and represent a vestigial or 

 rudimentary dimorphism ; they appear only to be found in the more populous colonies. 



This species is closely similar to N. arborum in certain features of both imago and 

 soldier, and differences have been given under that species. N. fulleri is also 

 related, but is separated in the soldier by its 12 segmented antennae, and in the 

 imago by its proportionately shorter hind tibia, and the ocellus being closer to the 

 eye. 



Dr. A. E. Emerson has selected and labelled as lectotype one of the type series, 

 but the designation has not been published hitherto : — 



Lectotype : Nyasaland : Zomba, iv.1899 (Cameron), lectotype imago and 

 paralectotype soldier, N. infuscatus (Sjostedt), Naturhist. Riksmus., Stockholm. 

 Other paralectotype imago and soldier, A.M.N.H. 



Type Material. Tanganyika : Usambara Mountains, Derema (Conradt), syn- 

 type soldiers, N. usambarensis (Sjostedt), Naturhist. Riksmus., Stockholm (others 

 in Berlin Mus.). 



Other Material (additional to that recorded in Sands, 1957). Congo : 8km. N. 

 of Rwindi Camp, 4. v. 1948, and Rwindi Camp, 5. v. 1948, 3 vials (A. E. Emerson), 

 A.M.N.H. 



Kenya : Shimba Hills, 4.VL1952 (W. A. Sands) and 13.vi.1952 (P. B. Kemp). 



Tanganyika : Ifakara, 30.ix.1949 (M. Luscher), A.M.N.H. ; Amani, 7-9.iL 

 1952, 3 vials, and Mwakijembe, 11. ii. 1952 (W. A. Sands). 



Mafia Island : 1937 (W. V. Harris). 



Pemba Island : Wete, ii.1952 (Packenham). 



