ANIMALS OF POND AND STREAM 



Field trip. On this trip the student should be provided with a net 

 similar to the one used for insects. The wire frame must be very strong 

 and the net need only be twelve or fifteen inches deep. Several pint jars 

 or wide-mouthed bottles should be taken. Go to pond or stream margin 

 and dredge for animals. Look under stones for crayfish and capture some. 

 Dredge along the weedy bottom, dumping the contents of the net into a pint 

 jar. Take this back to the schoolroom for later examination. Dredge out 

 material from several spots along the shore and dump the material obtained 

 on a bare spot on the ground. Pick out the animals as they wriggle out 

 of the material and put them in the pint jars partly filled with water. You 

 will probably have little difficulty in collecting the water sow bug and the 

 bender, both fair-sized relatives of the crayfish. Try to obtain, also, 

 dragon-fly and damsel-fly nymphs, mosquito larvae, larvae of the water 

 beetle, the May fly, and the stone fly. Take these back to the schoolroom 

 in the pint jars. If possible secure specimens of diving beetles, water 

 boatmen, back swimmers, and water scorpions, and learn to know the 

 whirligig beetle, water strider, caddis-fly larva, and the common water 

 spider. Quite likely several trips may be necessary to secure this material. 

 Take back in the jars some of the plants found growing in the water. On 

 the return to the schoolroom put several sprays of plants in the aquarium 

 jar on your desk and then dump in the animals brought back from the trip 

 that you especially wish to save. Fresh water may be added from the tap. 



Study of crayfish and its relations. Put the crayfish in a small glass 

 dish or shallow pan that is partly filled with water. Notice the parts of the 

 animal. In what ways is it like an insect ? in what ways different ? How 

 does it compare with the land sow bug ? How many feet has it ? Does 

 it use them all in walking ? Does it have any other means of locomotion ? 

 Stick your pencil point down near it. How does it behave ? How many 

 of the feet are provided with pinchers ? Are the great pinchers on the fore- 

 legs of equal size in all specimens ? Can you account for this ? What sense 

 organs can you see that the animal possesses ? How are the feelers used ? 

 Darken half of the dish: does the crayfish distinguish between light and 

 dark ? As the animal stands quietly in the dish look squarely at him from 

 in front. What do you see moving ? Drop a little powdered chalk into 

 the water just in front of him. How does this move as it sinks near him ? 



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