Bull. U. S. B. K. 1912. 



Pl.ATK LXXXIX. 



Fig. 79. — Photograph of outdoor troughs at Craig Brook. On the right, wooden troughs; 011 the hit, , <nKiit tanks. 



1 u.. iL'. -i'hulu;4r;iph .sh^.. .n- ant pond No. 11 at Craig Brook. 



