PLATE 26 



CADDIS-FLY AND CADDIS-CASES. 



Page 198 



An example of the four-winged flies whose aquatic grubs construct portable houses, 



varying in shape and material according to the species of builder. The upper ones 



are of grains of sand cemented, two of them strengthened by small sticks. The 



lower are of bits of wood, leaf and snail-shells. 



Photos by Author. 



