ETHIOPIAN NASUTITERMIT IX. \E 



'35 



setae, up to two-thirds length of long fine setae on posterior margins directed downwards and 

 slightly forwards. 



Minor soldiers : as major soldiers, except head capsule in plan more oval, sometimes slightly- 

 constricted behind antennae. 



Measurements (Major soldiers, 56 specimens from 20 localities, minor soldiers, 15 specimens 

 from 8 localities) in millimetres. 



Major Soldiers : 



Range 



Mean 



Head length to tip of nose 



2-04-2-96 



245 



Head width . 



1-09-1-76 



132 



1 >epth of head capsule . 



0-78-1-17 



091 



Width of pronotum 



0-55-0-84 



065 



Length of pronotum 



0-26-0-46 



034 



Length of hind tibia 



1 -43-2-45 



175 



Minor Soldiers : 



Range 



Mean 



Head length to tip of nose 



1-64-2-00 



1 -86 



Head width . 



078-1 00 



082 



Depth of head capsule . 



0-59-0-75 



065 



Width of pronotum 



0-48-0-61 



052 



Length of pronotum 



0-18-0-25 



024 



Length of hind tibia 



1-38-1-89 



i-54 



Variation. The range of variation in this species is very great : specimens from different 

 localities may differ from each other more than some genuine species from other parts of the 

 African continent. 



In the imago, the extremes of colour have been given, but there is also variation in the dis- 

 tribution of lighter and darker shades of pigmentation on head and body. The variation in 

 shape of head capsule, size of eyes and ocelli, and degree of inflation of postclypeus may com- 

 bine with colour patterns to produce a very different appearance. The soldier caste often 

 provides more reliable identification in this species. 



There appear to be variant forms of imago and soldier castes occurring more frequently in 

 certain ecological conditions, especially those associated with altitude. Several of these forms 

 were given specific names by earlier authors, on the basis of the more limited samples of 

 material available to them. These variants appear to be locally stable in limited populations, 

 but it must be emphasized that in the large amount of material now examined, every gradation 

 of intermediate between them has been found, and in addition a number of other minor forms of 

 only very local importance have been observed. 



In the most distinctive of these variants the imago head is dark brown and the pronotum 

 sepia brown, associated with a soldier caste in which the nose is rather short, slender, and dark 

 in colour. This was described by Fuller (1922) asfuscus, and appears commonest at altitudes 

 from 3,000-5,000 feet. 



The name trinervoides was applied by Sjostedt (1911a) to another form, most frequent in the 

 southern part of Cape Province, at moderate to low altitudes. The imago head capsule is more 

 broadly rounded posteriorly, and chestnut brown in colour ; the pronotum is yellow. The 

 associated soldiers have a rather short, thicker nose, though a thinner-nosed form was described 

 by Fuller (1922) as gemellus subsp. thomseni. In these southern specimens the postclypeus is 

 often more inflated than in those from further north. 



The third important variant is that in which the soldier caste is large with the nose longer 

 than the rest of the head ; the imago is similar in shape to fuscus although generally larger, 

 with trinervoides-type colouration, and often with larger eyes in proportion to its size than the 

 southern specimens. This form has been named hentschelianus (Sjostedt), trinerviformis 

 (Holmgren), havilandi and kurumanensis Fuller, and hilli Snyder and Emerson, from various 

 localities. It appears to be most common in the rather dry A cacia-Commiphora wooded steppe 

 and the slightly less dry intermediate savannah (Keay et al., 1959, vegetation types 25 and 20) 



