4 o W. A. SANDS 



in many higher Termitinae of wood- or herbage-feeding lines, but the molar plate 

 lacks ridges like that of Foraminitermes. The most distinctive feature of Pseudo- 

 microtermes is the intestine. The first segment of the proctodeum is short, ending 

 in a muscular unarmed enteric valve like that of Foraminitermes. The malpighian 

 tubules are inserted as bilaterally opposed pairs at the simple transverse mesenteric- 

 proctodeal junction. The gizzard has well-developed typical armature. Thus the 

 gut has many features in common with more primitive groups and the Macro- 

 termitinae, as do the external characters. Its general similarity to Foraminitermes 

 apart from the gut, and the paired malpighian tubules suggest that the only position 

 in which Pseudomicrotermes can be classified is as an extremely primitive offshoot 

 near the base of the Termitinae. The intestine of this genus is shown in Text-fig. 29 

 and the imago mandibles in Text-figs 30 & 31. 



Keys to Genera 



Before attempting to use the keys it will save time if the specimen to be identified 

 is first measured and a set of ratios is worked out. This can be done with a slide-rule 

 in a few minutes. The keys cannot be worked without the ratios which are essential 

 for discrimination between both genera and species. The measurements that are 

 required are given in the list of characters used for the multivariate analyses under 

 the heading (i) Continuous variables (p. 12). The characters concerned are numbers 

 35-59 inclusive. The fixed points for the more novel measurements are illustrated 

 in Text-figs 1, 2 & 3. It is important that the measurements be taken in millimetres 

 and expressed as decimal fractions, as in the tables given under species-descriptions. 

 If other units are used they will affect the scale of complex ratios with different 

 numbers of terms in numerator and denominator, resulting in gross errors. One 

 measurement is best left until actually needed, namely the greatest diameter of the 

 compound eye. This is normally completely size-correlated and of no value. 

 The only exceptions are found in the monotypic Amicotermes and two species of 

 Ateuchotermes. The ratios required are as follows: 



Imago and worker 



1. La/Li (left mandible index) 



2. Ra/Ri (right mandible index) 



3. L A /Li.L m (ratio 1 divided by L m , distance from third marginal to molar 



notch) 



4. Pcl/W (postclypeus length divided by head width) 



Imago alone 



5. La-Ra/LiXih (ratio 3 multiplied by Ra) 



6. Ri/Ra-Rhi (note difference from ratio 3 for left mandible) 



7. Pc1/Ra (postclypeus length divided by right apical to first marginal) 



8. M/W (mesonotum width at constriction divided by head width) 



9. Li/M.N (left first to third marginal divided by product of meso- and meta- 



notal widths) 



