i6 
Annals of the Transvaal Museum 
In the hostilis group of species, which are all diurnal in habit, it is 
noteworthy that the stridulatory ridges on the chelicerae are usually 
reduced or even quite absent in the males, but are well developed in the 
females. Whilst losing the power to stridulate, — for which, perhaps, they 
are compensated by increased speed, — the males at the same time add 
to their ornamental characters: the colours become more vivid, and the 
fringes of long hair on the legs more strongly developed, the adult male 
of such species as chelicornis and villosa being quite strikingly handsome. 
But often, as in derbiana, females are more brilliantly coloured than males. 
Stridulation is only audible to man in the case of the largest nocturnal 
species, and perhaps does not operate apart from mastication amongst 
most solifuges. The nocturnal species shew no sexual differences in colour 
ornamentation, nor in hair development on the legs. It is in fact the 
general rule in this genus, that all the species exhibiting specialisations 
of structure or of colour, in one sex or in both, are diurnal in habit: 
the nocturnal species are all primitive in structure and plain-coloured. 
DISTRIBUTION OF SPECIES. 
Owing to insufficiency of material, the distribution of the species 
cannot be profitably discussed except in the case of the genus Solpuga. 
The nocturnal species of Solpuga often have a very wide range of dis- 
tribution. The common species (S. Venator) of the Karroo and Eastern 
Province of the Cape extends far into South-West Africa, and another 
large nocturnal species (S. monteiroi ) in the northern parts of S. Africa 
seems to extend its range right across the continent from Delagoa to 
Walfish Bay. The common species of Johannesburg (S. schonlandi) 
occurs also at Kimberley, and in the Eastern Province of the Cape. 
The diurnal species on the other hand have usually a very limited 
distribution. Two diurnal species are only known from the Cape Penin- 
sula. No one species is known to range from the Transvaal to the Cape, 
and the species found near Pretoria and Johannesburg (S. hostilis) does 
not extend so far as Kimberley or Bloemfontein. In Das Tierreich, 
Kraepelin records S. marshalli from Mashonaland and from Durban, but 
this is no doubt incorrect. A partial exception to the general rule is 
found in species which occupy a large area of more or less uniform con- 
ditions. The handsomely coloured S. chelicornis thus ranges from Nama- 
qualand to the karroid regions of Eastern Cape Province, though it 
seems more than likely that this species is not uniform throughout, but 
composed of a number of structurally distinct forms. Solpuga hostilis , 
again, enjoys a fairly wide distribution over portions of the high and 
middle veld of the Transvaal and of adjoining parts in Natal. A still 
more extensive range has been indicated for 5. sericea Poc., the type of 
which came from Mashonaland, and which has since been recorded from 
the Zoutpansberg district by Dr Purcell, and from several localities north 
of the Zambesi by Mr Hirst : but this case is not so anomalous inasmuch 
as the species, though diurnal in habit, nevertheless belongs to the large 
primitive group which includes all the nocturnal species. 
When the species have been arranged into so many natural groups. 
