THE HUNTING SPIDERS 209 



ling prowess of our North American Dolomedes, enough to suggest 

 that the capture of tiny fishes is not a rare occurrence. While fishing 

 in a swampy region of the upper St. Johns river in Florida, Dr. 

 Thomas Barbour watched the capture of small cyprinodont fishes 

 by spiders that swarmed on the floating lettuce and other vegeta- 

 tion. "A tiny flash of silver caught my eye, and I looked again, to see 

 a spider carrying a small dead fish, perhaps an inch long, across a 

 wide leaf to the dark interior of a large lettuce cluster. I thought 

 that probably the spider had found a dead fish by chance and I relit 

 my pipe, when about six feet away in another direction the episode 

 was repeated. This time the little fish was still struggling feebly in 

 the spider's chelicerae. Later, I saw a third fish being carried off 

 which was dead and quite dry." 28 Some Dolomedes have been seen 

 to capture trout fry in hatcheries, and are considered capable of ac- 

 counting for a good number of such tiny fish. The owners of bal- 

 anced aquaria have sometimes been puzzled by the disappearance of 

 prize fish, subsequently to discover a spider robber with part of its 

 spoils. 



It is improbable that vertebrate prey forms more than a small 

 portion of the total food of the aquatic fisher spiders. One wonders 

 whether the toll even closely approaches the great number of 

 spiders of all sizes that are eaten by trout and other surface-foraging 

 fish. A far more frequent user of this food source than our native 

 species is such an exotic fisher as the African Thalassius. The skill 

 shown by this predaceous creature in capturing tiny fish, as reported 

 by the Reverend Nendick Abraham of Natal, is well worth men- 

 tioning: 



That night about 1 1 o'clock, when I had finished my day's 

 work, I sat down by the aquarium to watch the spider, with the 

 hope that I might see how the fisherman caught his fish. The 

 spider had taken up a position on a piece of stone, where the 

 water was not deep, and had thrown out its long legs over the 

 water, upon which their extremities rested, making little de- 

 pressions on the surface, but not breaking the "water skin." The 

 tarsi of the two posterior legs firmly held on to a piece of rock 

 just above the water level, the whole of the body was well over 

 the water, the head being in about the centre of the cordon of 

 legs, and very near the surface of the water. 



28 T. Barbour, "Spiders Feeding on Small Cyprinodonts," Psyche, Vol. 

 XXVIII (1921), pp. 131-2. 



