12 NATURAL HISTORY OF INSECTS. 



The SPIDERS (Arachnida) usually have the body divided into 

 two distinct regions (Fig. 9), the head and thorax being merged 

 into one part; the thorax and abdomen are frequently con- 

 nected by a slender stem or petiole. They do not past through 

 any changes or metamorphoses before reaching the adult 

 state. So far as at present known, all spiders are predaceous, 

 feeding upon insects, etc.; and one South-American species, 

 of very large size, is said to catch small birds by creeping up, 

 and springing upon them, like a cat. 



The Mites and Ticks differ from the Spiders in having the 

 three parts of the body closely united, as the Yellow Mite 

 (Fig. 10), there being no distinct line of separation between 

 the thorax and the abdomen. The young Mites are generally 

 provided with six legs (Fig. 11). Some kinds feed upon the 

 leaves, etc., of various plants; others feed upon the eggs of 

 insects or upon young plant-lice, such as the Phylloxera Mite 

 (Fig. 12); and still others live parasitically upon different 

 kinds of animals, such as the sheep Scab-Mite (Fig. 13), 



Fig. 12 Fig. 13 



The Scorpions belong to the same class as the Spiders, being 

 provided with eight legs; their maxillary palpi (or feeler at- 

 tached to the lower jaw), are frequently as long as their legs, 

 and terminate in forceps-like claws. They are mostly preda- 

 ceous in their habits. 



The Centipedes, Millipedes, etc., (Myriapoda) , are sometimes 

 called "Thousand-legged Worms," from the great number of 

 legs with which their bodies are provided (Fig. 6). They are 

 readily divisible into two groups, according to the number of 



