Bui. 1098, U. S. Dept of Agriculture. 



PLATE II. 



Fig. 1. — View aloii? channel, Bayou Walnut, natural conditions, showing overhanging vege- 

 tation and aquatic vegetation in bed. Surface of water in foreground covered with duckweed 

 (Lemna spp.) and with aquatic plant, Jussiaeu diffusa, in background. 



Fig. 2. — View across Bayou Walnut, natural conditions, showing absence of overhanging 

 vegetation, with aquatic grass, Zizaniopsis miliacea, in bed. 



IMPOUNDING WATER TO CONTROL MALARIA MOSQUITOES. 



