2 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 
On Some Ground-Dwelling Arachnida.* 
By B.C, imek, B. A. (Cantab:), Fk. M.S.) Wihittiers@al: 
Introduction. There are 5 orders of the class Arachnida 
which, owing to their nocturnal habits, and the consequent 
difficulty and inconvenience attending their study, have not 
received that general attention which they deserve. These 
interesting groups are: The Mygalomorphe, or large tube- 
dwelling spiders; the Seorpions; the Uropygi, or whip-secor- 
pions; the Solifugwe, or scorpion-spiders; and lastly the Am- 
blypygi, which are comparatively rare, and have no popular 
name, though their extraordinary appearance, something be- 
tween a spider and a bad dream, would make it an easy task 
to endow them with an appropriate title. 
I studied these groups during a residence of eleven years in 
the East Indies, and subsequently had the advantage of work- 
ing on the available material at the British Muesum, under the 
guidance of Mr. Pocock, the European authority on the Ara- 
ehnida. So, on arriving in Southern California, I naturally 
wished to study those representatives of the above-named or- 
ders peculiar to the Pacific Coast. Thanks to the courtesy of 
Mr. Lummis and of the staff of the Research department of the 
Public Library, I was put in touch with the national sources | 
of information; only to discover that whilst Dr. MeCook and 
Professor and Mrs. Peckham have dealt exhaustively with the 
American spinning-spiders, little has been published relating 
to the ground-dwellme Arachnida. True, I unearthed a paper 
by Mr. Nathan Banks, in which he names one species each of 
2 genera of Solifuge, and 3 out of the 4 genera of scorpions 
so far established in California. Of the others, no mention is 
made; and as the paper was evidently intended solely to iden- 
tify material sent for that purpose, no description was appended 
which would enable the student to recognize such specimens 
as he might find. 
It follows, therefore, that an open field is left for systematic 
work on these groups; and so I thought that a short epitome 
of their morphology and physiology might prove of interest to 
this society. It will, I hope, be found to be both aceurate and 
intelligible, though neither too superficial nor needlessly tech- 
nieal. This paper is partly the result of a personal study of 
the Arachnida of other lands, partly an epitome of other 
workers researches; and I offer it as merely a preliminary to 
detailed work on the Arachnida of Southern California. 
*Read before the Biological Section of The Southern California 
Academy of Sciences, Feb. 18, 1907. 
