10 
Annals of the Transvaal Museum 
bristles, the basal ones stout and strong and the distal ones much more 
slender. In older specimens, the feather bristles are more numerous and 
may occupy several rows. On examining a subadult male of S. derbiana, as 
yet without a flagellum proper, I find near the distal end of the feathered 
series several simple bristles of which one is markedly stouter than the 
rest and strongly curved like the feather bristles. This enlarged bristle, 
which seems to correspond with the single one at the distal end of the 
feathered series of juvenile specimens, is presumably destined to become 
the flagellum at the last moult. 
In such genera as Blossia and Hemiblossia the feather bristles of the 
adult, in both sexes, occupy only a single series of about 14-17 : they are 
all feathered, the distal ones often larger than, but not so strongly 
feathered as, the basal bristles. Daesia has more numerous bristles 
arranged in a double row in the adult, all being feathered. 
The primitive flagellum of the Daesiinae is simply a membrane with 
more or less infolded edges which basally unite to form a cup : the rota- 
table flagellum of Hexisopus and of Ceroma is probably to be derived 
therefrom by more extensive fusion throughout its length, whereby the 
free membrane becomes converted into a flattened tubular shaft: the 
fixed flagellum of Solpuga has a swollen basal enlargement which prob- 
ably corresponds to the cup-like base found in Blossia, and the more or 
less elongated shaft is usually if not always perforated by a fine canal 
along its length. The flagellum of Solpuga is far more variable in form 
than the primitive flagella of the Daesiinae and Hexisopodinae : in the 
least modified species such as suffusca, it lies on the flat or convex upper 
surface of the chelicera, but in various specialised forms of the hostilis 
group the basal portions of the flagellum become sunk into a distinct 
depression of the inner and upper surfaces of the jaw. 
In the Daesiinae the adult males are often provided with curiously 
modified bristles on the second abdominal sternite: these are absent in 
females or if present are not so highly developed as in males. 
When bristles and spines occur over the surfaces of the appendages 
and body they are more strongly developed in males than in females, 
except on the mesial surfaces of the jaws. 
Other secondary sexual characters are presented by the dentition, 
which is often greatly modified in the adult male but primitive in the 
female : the malleoli of males are much larger than those of the females : 
lastly, males are more slender than females, having longer limbs and 
smaller bodies but the disparity in size is not great. 
The adult male of Solpuga has an organ on the palp, viz. the Scopula, 
which is quite absent in females:. It is composed of numerous, closely 
packed, short, feathered hairs, which are presumably sensory in function. 
It is interesting to notice that a similar organ occurs on the tarsi of the 
legs in the adult male of Stasimopus (trap-door spider), but not in the 
female. I have elsewhere 1 presented reasons for regarding the Scopula 
of Stasimopus as an organ of smell. There is an important difference, 
1 "Note on the occurrence of a pedal nose in the male of a trap-door spider 
(Stasimopus)” in South African Journal of Science, March, 1917. 
