2o8 AMERICAN SPIDERS 



triton, a green-gray animal of moderate size. The upper part of the 

 cephalothorax is marked by two silvery white lines passing down 

 each side and continuing the whole length of the abdomen. A nar- 

 row white band runs from between the eyes to far back on the 

 cephalothorax, and the abdomen is further marked with four or 

 five pairs of small white spots. On the sternum are six dark spots, a 

 distinctive badge of triton which has given the name sexpunctatus 

 to a common form of the species. This spider is the most truly 

 aquatic of all our Dolomedes and haunts the wettest portions of 

 swamps and streams throughout the United States. It is often seen 

 on the water surface, its hind legs moored to the edge of a water 

 plant and its other legs far outstretched and lightly pressed into the 

 water film. When disturbed, it will run over the water and hide 

 in the aquatic vegetation, and when closely pursued it clambers into 

 the water and hides underneath leaves or debris. 



Dolomedes triton is a close relative of the English Dolomedes 

 fimbriatus, the "raft spider" of the Cambridgeshire fens. This 

 handsome fisher "has earned its name from its habit of constructing, 

 out of a few dead leaves and some threads of silk, a small raft on 

 which it sets sail on the face of the waters. From this raft it sallies 

 forth over the water in pursuit of its prey, for it can run easily on 

 the liquid surface." Although raft making has not been credited 

 to triton, very likely it occasionally utilizes similar small floating 

 islands when it hunts. 



The food of the amphibious fishers consists mainly of the larger 

 terrestrial insects from bank vegetation, and of aquatic insects in 

 various stages that are found crawling in the shallow water or living 

 on the muddy edges. On occasion, however, these predators have 

 been seen capturing small fishes and tadpoles and feeding upon their 

 bodies. This activity can be considered peculiar and surprising only 

 if the preconceived notion exists that spiders must feed solely on 

 insects and are unable to assimilate the bodies of vertebrates. The 

 truth of the matter is that spiders rarely hesitate to attack any 

 creature that comes within certain size limits. A tiny, squirming 

 fish, twice the size of the spider itself, is no more formidable an 

 opponent than a robust grasshopper, and is as easily dispatched. 

 The spider bites with its strong mouth parts, and its venom proves 

 very active on cold-blooded animals. Furthermore, its powerful 

 digestive juices appear fully as effective on the bodies of fishes as on 

 those of the invertebrates that are its habitual food. 



There are a number of well-authenticated instances of the ang- 



