ELEVENTH WEEK. 



Three species of insects should be determined this week. For di- 

 rections see under eighth week. 



ELECTIVE WORK Physiology (con.) 



GROUP IV. Effect of temperature. Needed: A number of ther. 

 mometers. A box with glass cover. A watch or metronome. A 

 musical instrument. A number of small potted plants and lamp globes. 

 Insects, some with a visible heart, some with evident respiratory 

 movements, some with sound perception, and some plant lice. 



TWELFTH WEEK. Carefully note the temperature and count the 

 heart beat. Place the insect and the thermometer in the box and set 

 upon the stove. After raising the temperature about 10 degrees F. re- 

 move and wait till the thermometer begins to fall, and count again the 

 heart beat Repeat, raising the temperature about ten degrees at a time 

 until it has become uncomfortable for the insect. If time remains, con- 

 tinue the observations while the box is cooling at each temperature be- 

 fore observed. 



THIRTEENTH WEEK. Repeat the above, counting the respiration 

 beats instead of those of the heart. 



FOURTEENTH WEEK. Repeat the above, countig nthe time re- 

 quired by a plant louse to walk over a certain distance under the differ- 

 ent temperatures. 



FIFTEENTH WEEK. Try to discover if there is any difference due 

 to the temperature in (a)acuteness of sound perception, ()pitch of best 

 perception, and (r)range of sound perception. 



SIXTEENTH WEEK. The work of this week should be started at 

 least six weeks before the end of the term. Make a number of breeding 

 cages, as directed under Life History Work, using, if possible rooted 

 plants. Put in each a thermometer and a newly born plant louse. One 

 cage should be placed out-of-doors, another in a living room, and a 

 third, if possible, in a still warmer place. It would be well to have two 

 in each place to allow for accidents. The thermometers should be read 

 three times a day as regularly as possible, and the insects examined. 

 At the end of six weeks the relative condition of each cage should be 

 carefully noted. 



