SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 125, NO. 1, PL. 16 



I. Young Stream that serves as the breeding grounds for S. ochracciun, the principal 

 vector of onchocerciasis in Guatemala. Note the abundant emergent and cover 

 vegetation. 



2. Adolescent stream, with tributaries and less abrupt walls than the young stream. 

 Union of Rios Queleya and Sacaya, Yepocapa. 



