THE SOLDIERLESS TERMITES OF AFRICA 39 



similarity matrix. These are compared in Text-figs 21, 22 & 23, with a hypothetical 

 dendrogram based on conventional criteria. The generic phenograms are self- 

 explanatory, the distances on the horizontal axes representing percentage similarities 

 as in the specific diagrams, although the actual figures are omitted. The hypo- 

 thetical phylogeny is drawn with the junctions equally spaced to represent closer 

 or more distant relationships without attempting to quantify them further. Its 

 main difference from the phenograms is the separation of two types of enteric valve 

 specialization. The first and most frequent tends to develop cushion positions 

 (see Text-fig. 18) 3 and 4 more than 1 and 2 as in Text-fig. 19, and progressing 

 beyond this stage to eversion through the valve opening. The other type has the 

 cushions all equally developed or position 1 extended as in Text-fig. 20. Many 

 of the relationships between genera are discussed in more detail under the generic 

 headings in later sections. 



Before leaving the subject of phylogeny and the subfamily classification finally 

 it is necessary to specify the fate of the rest of the Amitermitinae, to avoid leaving 

 certain difficult genera ambiguously placed. Apart from the list already given, 

 all other genera present classified in that subfamily become part of the Termitinae, 

 including Protohamitermes, Hoplotermes and Labritermes which have been regarded 

 as among the 'primitive Amitermitinae'. Protohamitermes has been discussed 

 earlier. Hoplotermes has a gut pattern virtually identical with Amitermes but has 

 adapted to soil-feeding. Labritermes is a curious genus that shares with Foramini- 

 termes a gut layout resembling some of the Termitinae only in having a dilated 

 first proctodeal segment. The malpighian tubules are attached separately to the 

 simple junction of mesenteron and proctodeum. They are evenly spaced and re- 

 flexed forwards on the midgut for a short distance before turning back towards 

 the hind gut in a similar manner to some Macrotermitinae. The soldiers of these 

 two genera have similar mandibles and both also have a hyaline tip to the labrum. 

 In the worker and imago castes the proportions of the mandibular teeth differ, 

 Foraminitermes having become adapted to soil-feeding by the elongation of apical 

 teeth and loss of molar ridges. In fresh unworn condition both genera retain the 

 second marginal tooth of the left mandible, while that of the right mandible is in 

 the primitive condition with convex anterior and concave posterior edges. Their 

 mandibles are illustrated in Text-figs 25 & 26, 27 & 28. They must be regarded as 

 among the most primitive members of the Termitinae, that not unexpectedly have 

 features in common with similarly placed members of other subfamilies. 



One further genus appears to be related to Labritermes and Foraminitermes in 

 many respects. The soldier of Pseudomicrotermes has similar mandibles and a 

 hyaline tip to the labrum. The fontanelle is open and grooves lead forward from 

 it to the base of the labrum. The imago closely resembles that of Foraminitermes 

 in colouring, pilosity, the small open fontanelle raised on a minute projection, and 

 the saddle-shaped pronotum. The tibial spurs number 3 : 2 : 2. The proportions 

 of the apical teeth of imago and worker mandibles are intermediate between the 

 two former genera. In fresh unworn specimens of the imago, the second and third 

 marginal teeth of the left mandible are similarly developed to those of Labritermes. 

 The second marginal of the right mandible has the straight-edged cutting form seen 



