6 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 
production. To each of these aspects, in the order named, I 
invite your attention. 
A glance at any of the Arachnida shows that they are as well 
equipped for a predatory career as a political ‘‘boss.’’ The 
pineers and sting of the scorpion, the grappling-nooks of the 
Phrynichide, the jaws and pincers of the whip-tails and the 
scorpion-spiders, and the poison-fanes of the spider all serve 
the same end, namely, the securing of the various kinds of live 
food on which the different orders feed. 
The sting and fangs of the scorpion and spider respectively 
are needed to enable them to secure such relatively powerfull 
victims as cockroaches and large flies. The poison secreted 
seems to partake of the properties of snake-venom rather than 
those of insect poison It does not appear to irritate the tis- 
sues, as, for example, does the sting of a bee; but, lke the 
venom-peptone and venom-globulin of the snake, acts rather 
on the motor-centres through the circulation. And the cause 
of this difference may be found, if we consider the end in view 
in each case. The bee’s sting is only needed to secure im- 
munity from molestation, and to effect this purpose it need not 
be fatal: it suffices that irritation in greater or less degree 
should be caused. But the scorpion and spider need to secure 
a meal; therefore their poison must be able to at least paralyze 
their prey. It is interestme to watch the swift dart of the 
large Indian scorpion, Palamneus, on a cockroach. It catches 
the insect in its powerful pincers, leisurely (at least, such is the 
impression given) feels about with the sting till the right spot— 
usually the upper part of the thorax—is found, when the sting 
is firmly pressed, rather than struck, home; and the scorpion 
waits for the poison to take effect before beginning its meal. 
The scorpions of Southern California are not nearly so large 
as many tropical varieties, some of which attain a length of 
185 mm. or over 71% inches; but as a rule the effects of the sting 
of the smaller kinds are more poisonous than those of the 
larger. 
The scorpion-spiders are strictly nocturnal in their habits, as 
their name Solifugz indicates. . They feed chiefly on ants, and 
hence do not need poison so much as activity, to enable them 
to secure their prey. Their speed is simply astounding, and 
they are by far the swiftest of all the Arachnida. They flit 
about like shadows, and for this reason it 1s no easy matter to 
secure them. Nor are they very common except in desert and 
sandy loealities. 
The Phrynichide are more sluggish than the preeedmg; and 
hunt in much the same fashion as does the toad. An insect 
will alight, apparently well out of range; but the extraordi- 
