Ernest Warren 
331 
and when such occurs it was found that the measurement could be more con- 
veniently and accurately taken if the breadths of the eyes were included in the 
dimension. It is certain that the inclusion of the eyes in such cases has no 
appreciable effect on the results, as the correlation of the size of head and eyes is 
exceedingly close ; and the eyes being partially sunk in the exoskeleton complete 
the contour of the head. It should be noticed that the dimensions taken of the 
different castes are not perfectly homologous, for some soldiers are blind and others 
have curiously shaped heads ; but they are as nearly homologous as the nature 
of the case admits, and they may all be regarded as closely comparable measure- 
ments. 
The measurement of the selected dimension may be made with sufficient 
accuracy on account of the comparatively rigid nature of the exoskeleton of the 
head. Length or breadth measurements of the abdomen would have been quite 
unreliable. 
The specimens were in all cases preserved in alcohol. 
The method of measurement adopted by Mr Haviland is not recorded in his 
notes ; but I have no hesitation in accepting his data as thoroughly trustworthy. 
The method which I found most satisfactory was to examine the specimen under 
an 'aa' or ' AA' Zeiss objective with a camera lucida, and to mark ofT the dimension 
on a slip of paper. The termite was flooded with spirit on a slide, and orientated 
by means of a small piece of glass placed above it. The slip of paper was referred 
to a scale made with the camera from a stage-micrometer (divided into and 
mm.) viewed under the same magnification, and the absolute dimension could 
thus be read off. One or two small series measured by Mr Haviland were 
re-measured by my method and the results were in close accord. 
The measurements of Termes natalensis will be first dealt with, and sub- 
sequently a comparative review of some of the Natal species of termites will 
be made. 
(3) Termes natalensis Haviland. 
As we have already seen a colony of this species consists of one queen and 
king, numerous soldiers of two sizes and workers of two sizes, also immature young 
or larvte, and at certain seasons nymphs of males and females, which on becoming 
winged leave the nest as a swarm. 
In the accompanying table the means, standard deviations and coefficients 
„ . . /Standard Deviation ,-^\ „ • i i,i ^ A-ce i. 
or variation ^. x 100 of a considerable number of different 
Mean 
colonies are shown. The measurements refer chiefiy to the soldiers and the 
workers : where the material was available the queen and king were measured, 
and in nest No. " 653 " one hundred male and one hundred female nymphs with 
wing-rudiments were measured (see Table VIII.). 
The nests are arranged in the table according to the season of the year at 
which the material was collected, beginning with November. 
42— -2 
