TYPICAL GROUP 



3191 



the posterior pair alone remaining, and being represented on each side by a long 

 external jointed branch and a short inner one-jointed branch. Sometimes, how- 

 ever, two mammillae of the front pair are retained. The eyes generally form a 

 compact group but the lateral eyes on each side may be widely separated from 

 the median pair. 



Several families, passing almost imperceptibly into one another, are comprised 

 in the group. Among these, the bird-catching spiders {Theraphosid<z) are the 

 giants of the order. They include several genera, such as Avicularia and Poeci- 

 lotheria; a species of the latter being shown in the accompanying illustration. Usually 

 they are dark brown or black in color, and clothed with short hairs mingled with 



BANDED BIRD-BATING SPIDER (Pixcilotheria fasciata). 



bristles. The lower surfaces of the feet are covered with a thick pad of silky hair, 

 furnished with adhesive power, by means of which these spiders are able to climb 

 vertical sheets of glass. The claws on the feet seem to be of but little service, being 

 small and generally concealed among the hairs. There are a large number of species 

 and genera distributed over all tropical and subtropical countries; the largest 

 species occurring in the northern parts of South America, where specimens almost 

 equalling a rat in size are met with. The males are always smaller than the 

 females, being of lighter build, longer in the leg, and consequently more agile. 

 These spiders spin no web for the capture of prey, living either in holes in the 

 ground or beneath stones and silk-lined logs, or in silken tubes which they spin in 



