MYGALILM. 169 



stones, plants, ana other objects. The young resemble their parents in general form and structure, 

 and undergo no metamorphosis. 



In their habits the Spiders are all predaceous, arid their prey consists almost entirely of small 

 Arthropods, especially insects. In the capture of these they adopt various devices : some of them 

 creeping about among plants and such objects until they find themselves within reach of a desirable 

 booty, or lurking in dark corners to rush out upon any passing victim, others directly pursuing the 

 fly or other insect that they have selected with a genuine cat-like stealthiness, while others weave 

 most beautiful and ingenious snares for the capture of their prey. In all cases, however, the fate of 

 the victim is the same ; the Spider buries the claw-joints of its falces in the body of its prey, the 

 juices and softer parts of which are then sucked out by the action of the muscular apparatus 

 appended to the ossophagus. 



Of this order several thousand species are known from all parts of the earth, but they are nearly 

 all of small or moderate size, with the exception of a few tropical members of certain families 

 which attain comparatively gigantic dimensions. In general the species inhabiting warm countries 

 have little advantage in point of size over their relatives in temperate climates. The species are, 

 however, more common in warm regions. 



Fossil Spiders are not numerous, especially in the older rocks. Nevertheless, species occur in the 

 Lithographic Slates of Solenhofen, and, as in the case of the Scorpions, one or two have been recorded 

 from the Coal Measures of Silesia and Bohemia. They are more numerous in the Tertiary insect- 

 beds, and a great many have been preserved in amber. 



In the classification of the great number of Spiders forming this order there is not unnaturally 

 some little difficulty, and the consequence is that nearly every original author adopts a method of his 

 own, the results of which, as regards the bringing together of the different forms, are often very 

 divergent. The following division into families, which is a slight modification of Gerstacker's arrange- 

 ment, will serve, we think, to give the reader a good general idea of the mutual relations of the 

 different types : 



I. Two pairs of lung-sacs and two pairs of spinnerets ; claws of falces 



bending downwards ....... Tribe I. TETRAPNEUMONES. 



One family ... ..... Family 1. MYGALID^E. 



II. One pair of lung-sacs ; usually six or eight spinnerets ; claws of falces 



bending inwards . Tribe II. DIPNEUMONES. 



A. Tagabundte. Ocelli usually in three rows ; wanderers which spin no 

 webs : 



* Cephalothorax nearly rectangular ..... Family 2. SALTICID.B. 

 t Cephalothorax narrowed in front ..... Family 3. LYCOSID^E. 



B. Sedentaria. Ocelli in two rows ; makers of webs for the capture of 

 prey: 



* Abdomen broad and depressed . . Family 4. THOMISID^:. 

 t Abdomen moderate, or, if broad, very convex : 



a. Intermediate pairs of legs shorter than the others ; webs more 



or less tubular ....... Family 5. TEGENARIIDJE. 



b. First pair of legs usually the longest; webs irregular . . Family 6. THEKIDIIDJE. 



c. First and second pairs of legs longer than the otbers ; webs 



with more or less regular radiating and concentric lines . Family 7. EPEIRID.B. 



TRIBE I TETRAPNEUMONES. 

 FAMILY I. MYGALID.E. 



The group of the Tetrapneumones, or Four-lunged Spiders, which includes only the single family 

 of the Mygalidse, is distinguished not only by the presence of four stigmatic openings towards the 

 base of the abdomen, but also by the possession of only four spinnerets, two of which are very 

 small, and by having the claw of the falces bent downwards, so that those organs are kneed. This 

 family includes a number of species, for the most part of large or considerable size, and some of them 

 among the very largest of Spiders. They are mostly confined to the warmer parts of the world, only 

 a few, and those comparatively small, extending their range into southern Europe, while a single 

 species alone is recorded as an inhabitant of Britain. 

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