428 ARACHNIDA—SOLIFUGAE CHAP. 
The nervous system, notwithstanding the fact that the three 
last thoracic segments are free, is chiefly concentrated into a 
mass surrounding the oesophagus. Nerves 
are given off in front to the eyes, the 
labrum, and the chelicerae, while double 
nerves radiate to the pedipalps and to 
the legs. From behind the nerve-mass 
three nerves emerge, and pass through 
the diaphragm to enter the abdomen. The 
median nerve swells into an “abdominai 
ganglion” just behind the diaphragm, and 
is then distributed to the diverticula of 
the alimentary canal. The lateral nerves 
innervate the generative organs. 
The respiratory system consists of a 
connected network of tracheae communi- 
cating with the exterior by the stigmata, 
whose position has already been described. 
Fic. 218.—Nervous system There are two main lateral trunks extend- 
CCE Tae: oe ing nearly the whole length of the body, and 
cheliceral nerve; ch.f, giving off numerous ramifications, the most 
chitinousfold ; ch.r,chitin- important of which are in the cephalo- 
ous rod; g.n, generative 
nerve; J, labial nerve; thorax, and supply the muscles of the 
Ree stigma. chelicerae and of the other appendages. 
The generative glands do not essen- 
tially differ from the usual Arachnid type, though the paired 
ovaries do not fuse to form a ring. There are no external 
organs, and the sexes can only be distinguished by secondary 
characteristics, such as the “ flagellum” already mentioned. 
Classification. There are about a hundred and seventy 
species of Solifugae inhabiting the warm regions of the earth. 
No member of the group is found in England, or in any except 
the most southern portions of Europe. 
Kraepelin! has divided the group into three families—Galeo- 
didae, Solpugidae, and Hexisopodidae. 
Fam. 1. Galeodidae.—The Galeodidae have a lancet-shaped 
flagellum, directed backwards. There is a characteristic five-toothed 
plate or comb covering the abdominal stigmata. The tarsus of the 
fourth leg is three-jointed, and the terminal claws are hairy. 
1 Das Tierreich, Berlin, 12. Lief., Arachnoidea, 1901, p. 4. 
