THE RATT SPIDER. 597 



temporary and moveable residence. This is the Raft Spider 

 (Dolomedes Jumhriatus) which is represented in the illustration of 

 its natural size. 



As may be seen by reference to the figure, it is a large species, 

 being, indeed, one of the largest British spiders, its size depend- 

 ing more upon the dimensions of the body than the length of 

 the limbs. It is a remarkably handsome spider, its general 

 colour being chocolate-brown, and a broad orange band being 

 drawn so as to mark the outline of the abdomen and thorax. 

 There is a double row of small white spots upon the surface of 

 the abdomen, and a number of short dark transverse bars give 

 variety to the colouring. The Umbs are pale red. 



This creature belongs to that group of spiders which do not 

 live in a web, and wait for casual insects, but which chase their 

 prey after the manner of carnivorous vertebrates. Indeed, it may 

 fairly be said to belong to the large group of wolf spiders, and is 

 nearly allied to them. 



The Eaft Spider is only to be found in fenny or marshy places, 

 and is mostly seen in the fens of Cambridgeshire, where its 

 remarkable habits have long been known. Not content with 

 chasing insects on land, it follows them in the water, on the 

 surface of which it can run freely. It needs, however, a resting- 

 place, and forms one by getting together a quantity of dry 

 leaves and similar substances, which it gathers iuto a rough ball, 

 and fastens with silken threads. On this ball the Spider sits, 

 and allows itself to be blown about the water by the wind. 

 Apparently, it has no means of directing its course, but suffers 

 its raft to traverse the surface as the wind or cunent may 

 carry it. 



There is no lack of prey, for the aquatic insects are constantly 

 coming up to breathe the air; and although they may only 

 remain on the surface for a second or two, the Spider can seize 

 them before they can gain the safe refuge of the deeper water. 

 Then there are insects, such as the gnat, which attain their 

 wings on the sm-face of the water, and can be taken by the 

 Spider before they have gained strength for flight. Also, there 

 are insects which habitually traverse the water in search of prey, 

 and which are themselves seized by the more powerful and 

 equally voracious Spider. More than this, moths, flies, beetles, 

 and other insects, are continually falling into the water, and 



