66 Field Columbian Museum — Zoology, Vol. Ill, 



rainy season, at which time the Rio Conchos at Jimenez becomes 

 200 or more feet in width and as much as 15 feet in depth. 



The Lago de Castillos System. 



This lake receives the water from a large depression on the 

 divide between the head waters of the Rio Conchos and the Rio 

 Yaqui. Lago de Castillos is a large body of water in the wet 

 season, but nearly all of its water is evaporated by the end of the 

 dry season. The seining of a few holes yielded but one species 

 of fish. A few small fishes are reported in some of the springs on 

 the margin of the lake bed even in the dry season. These are 

 either the young of L. nigresceas, or are possibly Cyprinodon ele- 

 gans and Notropis h/trensis, more likely all three of these. I was 

 unable to visit any of these springs, as my time when I visited 

 Bustillos was limited. The Bustillos hacienda comprises most 

 all of this drainage area. 



The Rio Yaqui System. 



The Rio Paphigochic, a tributary of the Rio Yaqui, was visited 

 at Mihaca. This river contained a small amount of running water. 

 Its current was rapid and flowed over beds of sand and gravel. 

 We collected in the deep holes and shallow places along the river 

 for about a mile. The similarity of the fishes in this stream and 

 the Rio Conchos is very striking. 



The Tarahumares, a tribe of Indians living south of Mihaca, 

 catch fishes by poisoning the water with some herb. This is 

 reported to make the fish drunk. This is evidently a method 

 similar to the one used by the Cherokee Indians in the Indian 

 Territory. The Cherokees pound up the roots of the walnut and 

 mix the juice with the water. I have never seen this operation, 

 but from the description I have heard of it, it seems that the wal- 

 nut juice in the water acts as an astringent on the gills of the 

 fishes, no doubt causing a smothering sensation. The fishes 

 become active for a while and often swim with force enough to 

 land themselves high and dry. Later, if they remain in the 

 water, they become stupefied and are easily caught. Mr. A. G. 

 Maddren, who visited the Caroline Islands a few years ago, 

 informed me that some herb there was pounded up and its juice 

 mixed with the water to capture tide-pool fishes. It is interest- 

 ing to note this method of taking fishes by natives in three such 

 widely separated localities. 



