SPIDERS, SCORPIONS, AND MITES. 185 
types of the evil spirits ; a supposition not unwarranted, 
by the expression of our Blessed Lord, “ Behold, I give 
unto you power to tread ou serpents and scorpions, and 
over all the power of the enemy!”* Yet oven these re- 
pulsive animals arc the handiwork of Infinite Wisdom; 
and half-an-liour may be worse spent than in briefly run- 
ning over some of the peculiarities of their structure and 
habits. 
And, first, a few words on their structure. They may 
at once be distinguished from true Insects by having four 
pairs of legs instead of three. They exhibit a greater 
condensation of outward form, there being generally but 
one division, that which separates the abdomen from the 
fore part, which latter, because it includes in one the parts 
answering to the head and chest of insects, is commonly 
called the cephalothorax. The head is destitute of antennae, 
but those organs are replaced by a pair of claws terminat- 
ing either in a single hook, or in pincers. The eyes are 
always simple lenses, sometimes moderately numerous, 
and then usually arranged in groups, and occasionally 
placed at the summit of a sort of pillar on the back, a 
provision which must greatly assist circumspection. 
Internally, also, tho organisation is more condensed, 
and of a higher type than in Insects. The nervous knots 
or ganglia are few and central, sending out radiating 
threads to the circumference and extremities. The breath- 
ing organs are either luugs, enclosed in bags, or radiating 
air-tubes (tracheae), which communicate with the atmo- 
sphere by minute slits in the skin. The Spiders and 
Scorpions belong to the former category, and are named 
* Luke x. 19. 
