6cs 



CADDIS FLIES. 



Probably most of my readers have at some time or other, 

 stretched thej:;selves at full length on the bank of the 

 brook and idly watclied the things that went by with the 

 current or that made up the bed of the brook. Many 

 curious things may be found in the brook. 



Perhaps the bottom of the brook is covered with pebbles. 

 As you watch you may be astonished to see some of these 

 pebbles moving, — not only moving but travelling slowly 

 against the current. Let us take one of the moving peb- 

 bles and look at it closely: — We find it is not a pebble but 

 a lot of little pebbles firmly held together; still further 

 investigation shows that it is not solid but is a hollow tube 

 of pebbles lined on the inside with silk. We look inside, 

 but see nothing. Put it carefully in shallow water where 

 you can watch it closely. Presently it rocks a little, then 

 a head appears at the opening, then a quarter of an inch 

 of body, its tiny legs frantically clawing at the bottom; 

 at last they get a grip, the pebble house turns over into a 

 tetter position and under the influence of a sti-ong pull 

 slowly moves ahead. 



The occupant of this novel house is the caddis worm, 

 larva of the caddis fly. There are a good many species of 

 C"ddis flies, the larvae of all of them living under water. 

 All of these worms build some sort of a house, — some use 

 pebbles, some tiny sticks or straws and some leaves. What- 

 ever they are made of, the material is held firmlj' together 

 with silk spun from the mouth of the worm, and the civity 

 is smoothly lined with the same material. You often see 

 several styles of homes side by side in the same brook. 



Of course the object of making these houses is a pro- 

 tective one; there are many predatory water beetles that 

 would te glad to get at such toothsome morsels as ciddis 

 worms but the latter either escape notice or their armor is 

 too strong. Some of these cases are anchored to larger 

 stones or pebbles but the majority of them are free to 

 drift or to be carted about by their occupants. 



