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 on serpents and scotyions, and 

 over all the power of the enemy ! " * Yet even these re- 

 pulsive animals are the handiwork of Infinite Wisdom • 

 and half-an-hour 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, the 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 lungs, enclosed in bags, or radiating 

 air-tubes (trachea), 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. 



