224 WEB-SPIDERS. 



between them and the tailless Pedipalpi. It likewise resembles the latter 

 in the structure and situation of the breathing-organs, and also in the mode in 

 which the mandibles are articulated to the cephalothorax ; their basal segments 

 being directed forwards, parallel to each other and the long axis of the body, while 

 the second segments or fangs are directed backwards, also nearly parallel to the 

 longitudinal axis. The eight eyes are situated on a tubercle close to the front 

 edge of the flat and broad carapace ; the median being small, and the lateral 

 larger and placed in a semicircle on each side. The long and powerful legs are 

 armed with spines, and tipped with three claws ; their coxae being long, whereas 

 those of the palpi have no long maxillary process as in most other spiders. This 

 group comprises only the family Liphistiidce, with the genus Liphistiiis, of which 

 there is one species from Penang, and another from Sumatra ; both of large size, 

 measuring about 2 inches in length. Nothing is known of their habits. 



Typical Group, — Suborder Opisthothelae. 



In this group the abdomen is not segmented, and the spinning mammillae — of 

 which there are never more than six, owing to the disappearance or fusion of the 

 inner branches of the first pair of appendages — have moved to the hinder extremity 

 of the abdomen. It is separable into the sections Mygalomorphcu and Arach- 

 nomorphce. The former group includes the forms making the nearest approach 

 to the preceding suborder. The spinning mammillae are reduced in number, being 

 usually only four, owing to the disappearance of the anterior pair of appendages, 

 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 com- 

 prised in the group. Among these, the bird-catching spiders (Theraphosidai) are 

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

 Poecilotheria; a species of the latter being shown in the illustration on p. 225. 

 Usually they are dark brown or black in colour, and clothed with short hairs 

 mingled with 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 amongst 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 the hollows or upon the forked branches of trees. At night they 

 issue forth in search of food which for the most part consists of beetles and 

 other insects ; but they will destroy and eat any living creature weak 



