io6 ROMANCE OF THE INSECT WORLD CHAP. 



plants, of bits of stick, leaves of grasses, minute 

 pieces of bark and wood, fresh or decayed, of grains 

 of sand, or gravel or mud, of hay, and any such debris 

 that may have fallen into the water. Small fresh- 

 water shells, yet occupied by their living inhabitants, 

 are even affixed by the caddis to its case by their 

 flat exterior, and the material or materials are glued 

 together with a waterproof cement. The tubes tend 

 to assume the cylindrical shape, and the interiors are 

 lined with silk. Sometimes short lengths of plant 

 stems are placed longitudinally side by side, with 

 the utmost regularity, to form a perfect and shapely 

 cylinder, perhaps four inches long. The morsels 

 may be wound spiral fashion, or may be dis- 

 posed into a many-sided structure, and so on in 

 endless variety of arrangement. The larvae are each 

 provided with two hooks on the soft skin of the 

 end of the abdomen, so as to anchor itself firmly to 

 its house. When about to undergo metamorphoses 

 they fix their dwelling to something, and block 

 up the ends, not with a solid stopping, with a kind of 

 open fence, which, while it prevents the intrusion of 

 enemies, allows free percolation of the water in and 

 out. The adults may be observed any evening 

 in summer flying about the banks of streams and 

 marshes. The female enters the water to lay her 

 eggs, which previous to this event she keeps for a 

 short time in a green bundle attached to her body, 

 her object being probably to expose them to the 

 warmth of the sun before immersion. Enveloped in 

 a glutinous mass they adhere to an aquatic plant, or 

 to a stone. Upon an insect being hatched it im- 



