Insect Study 



387 



THE CADDIS-WORMS AND THE CADDIS-FLIES 



Teacher's Story 



EOPLE are to be pitied who have never tried to fathom 

 the mysteries of the bottom of brook or pond. Just to 

 lie flat, face downward, and watch for a time all that 

 happens down there in that water world, is far more 

 interesting than witnessing any play ever given at 

 matinee. At first one sees nothing, since all the swift- 

 moving creatures have whisked out of sight, because 

 they have learned to be shy of moving shadows; but 

 soon the crayfish thrusts out his boxing gloves from 

 some crevice, then a school of tiny minnows "stay 

 their wavy bodies 'gainst the stream;" and then 

 something strange happens ! A bit of rubbish on the bottom of the brook 

 walks off. Perhaps it is a dream, or we are under the enchantment of the 

 water witches! But no, there goes another, and now a little bundle of 

 sand and pebbles takes unto itself legs. These mysteries can only be 

 solved with a dip-net and a pail half filled with water, in which we 

 may carry home the treasure trove. 



When we finally lodge our catch in the aquarium jar, our mysterious 

 moving sticks and stones resolve themselves into little houses built in 

 various fashions, and each containing one inmate. Some of the houses 

 are made of sticks fastened together lengthwise; some are built like 

 log cabins, crosswise ; some consist simply of a hollow stem cut a con- 

 venient length ; and some are 

 made of sand and pebbles, 

 and one, the liveliest of all, is 

 a little tube made of bits of 

 rubbish and silk spun in a spir- 

 al, making a little cornucopia. 

 On the whole, the species 

 which live in the log cabins 

 are the most convenient to 

 study. Whatever the shape 

 of the case or house, it has a 

 very tough lining of silk, which 

 is smooth within, and forms 

 the framework to which the 

 sticks and stones are fastened. 

 These little dwellings always 

 have a front door and a back 

 door. Out of the front door 

 may protrude the dark-col- 

 ored head followed by two 

 dark segments and six per- 

 fectly active legs, the front 

 pair being so much shorter 

 than the other two pairs that 

 they look almost like mouth 

 palpi. In time of utter peace, 

 more of the little hermit 



Log cabin caddis-worms in their cases feeding 



upon a water plant. 



Photo by J. T. Lloyd. 



