LETTER OF TRANSMITTAL. 



DIVISION OF BIOLOGICAL SURVEY, 



Washington, D. C., January 25, 1899. 



SIR: I have the honor to transmit herewith for publication as North 

 American Fauna No. 14 a report by E. W. Nelson on the natural his- 

 tory of the Tres Marias Islands, Mexico. These islands are the largest 

 off the west coast between Cape St. Lucas and the Isthmus of Panama, 

 but have seldom been visited, and very little is known of their fauna 

 or flora. For several years Mr. Nelson has had charge of the field 

 work of the Biological Survey in Mexico, and in May, 1897, visited 

 the Tres Marias. During the course of this visit he made a thorough 

 collection of birds and mammals and also secured specimens of reptiles, 

 fishes, mollusks, crustaceans, and plants, so that his report contains a 

 fairly complete account of the natural history of the islands. In work- 

 ing up the material collected, Mr. Nelson has had the assistance of 

 several well known naturalists in the United States National Museum 

 and United States Fish Commission, who have prepared reports on 

 special groups, as credited in detail on page 13. 



Mention should be made also of the unfailing courtesy and interest 

 of the Mexican Government in the investigations conducted by the 

 Biological Survey in Mexico. Letters have been furnished by officials 

 in the City of Mexico, and by the late Mexican minister in Washing- 

 ton, Sefior Don Matias Romero, which greatly facilitated the work in 

 various ways, and on the occasion of the visit to the Tres Marias 

 enabled Mr. Nelson to borrow a large boat at San Bias and secure 

 comfortable quarters on the islands. 



Several attempts at agriculture have been made on the Tres Marias 

 Islands, but the results have thus far been unsuccessful, owing to the 

 dry climate and the scarcity of permanent water. Corn and beans 

 have been grown on a small scale, but the crops suffer from the severe 

 storms which occur at certain seasons. Experiments have been made 

 with a view to utilizing the native species of agave for fiber and mes- 

 cal, and the cultivation of cotton has also been tried without success. 

 Recently it has been proposed to establish an American colony on one 

 of the islands for the purpose of growing coffee, bananas, Australian 



