Species of Tropical African Solifuge. 269 
of this year from Natal, he says :—‘ With regard to the 
stridulation of Solpuya, I must admit that [ am almost 
becoming sceptical about it, at least in the species with which 
I am acquainted, for, though I have examined them carefully, 
on no occasion have I been able to detect any signs of stridu- 
lation, even when they have been persistently annoyed. And, 
moreover, I find it is impossible to produce it artificially by 
rubbing the chele together. Is it not possible that the striz 
[ fine upstanding ridges] might be useful in compressing food 
tor the extraction of the juices?” 
Touching the function of the palpi, and commenting upon 
Hutton’s observation showing that they are used as suckers 
in climbing slippery places, he remarks :— As far as I can 
see they seem to be used merely as tactile or, perhaps, auditory 
organs. ‘They are usually carried well forward just off the 
ground, and appear to be highly sensitive.” But in a sub- 
sequent letter he adds:—“ I have been further investigating 
the use of the terminal organ on the palpus, and am fully 
satisfied that Hutton was right in supposing it to be a sucker. 
I first noticed this when teasing a specimen with a straw and 
trying to make it stridulate. The creature struck sharply at 
the straw with its palpi, pulling it slightly towards itself. 
Wondering how it was able to grasp the object, I tried again, 
and distinctly saw a gelatinous fan-shaped sucker protruding 
from the palpal knob and sticking firmly to the straw..... 
I feel tolerably sure that the chief use of the sucker, which is 
evidently a very delicate organ, is for the purpose of grasping 
prey and conveying it to the mandibles. Owing to the 
extreme rapidity of their movements, it is almost impossible 
to observe exactly how they catch insects, but my general 
impression has always been that the prey is first caught by 
the palpi, and not by the mandibles direct.” Specimens 
kept in captivity “ devoured all sorts of small insects most 
voraciously, and, while eating, in addition to moving their 
nipper-like mandibles vertically, they also moved them alter- 
nately backwards and forwards in a horizontal direction.” 
With regard to general habits it is interesting to note that 
species of the same genus, Solpuga, are either diurnal or 
nocturnal. For example, Mr. Marshall was informed by a 
man ‘that when he was recently encamped at Hartley Hills 
he was forced to move his tent on account of its being over- 
run by a number of enormous spiders, evidently, from his 
description, a large Solpuga [probably S. Darlingit], which 
came in at night one at a time, attracted apparently by the 
light, and simply flew about it at lightning speed.” On the 
other hand, Mr, Marshall writes: “ When walking into Hartley 
