New York, July 24, 1916. No. 33 



CFE1 -ju 



Published to advance the Science of cold-blooded vertebrates 



THE VORACITY OF THE SOUTH 

 AMERICAN HOPLIAS 



Many of the sucker-like and carp-like Characins, 

 such as Prochilodus and Leporinus when caught in 

 the seine will lie quietly dormant, but Hoplias, if per- 

 mitted to remain undisturbed, is almost certain to 

 bite its way out. This habit, said to be fairly common 

 in the fishes of the Amazonian basin, is not often 

 found in the fishes of the Pacific coastal streams. 



In May, 1913, when upon the Landon Expedi- 

 tion of Indiana University, I was collecting in the 

 Rio San Juan of Western Colombia. One morning 

 at one of the Indian ranchos, where we had passed 

 the night, one of the Indians brought in a large Hop- 

 lias, which he had evidently caught with hook and 

 line and had dispatched by the crash of a machete 

 through its brain. This specimen measured about 

 twenty inches and had the abdomen greatly distended. 

 The Indians called my attention to this and upon 

 opening the fish, we took out an eight-inch catfish 

 (Pimelodus wagneri) . This, with the head of its cap- 

 tor, I procured in exchange for a few fish-hooks and 

 they are now in the Museum of Indiana University. 



Like most of the South American catfishes, Pime- 

 lodus is equipped with a very sharp dorsal and strong 

 jagged pectoral spines. Just how Hoplias can man- 

 age to capture these fishes is not known, It is quite 



