220 JOHN E. GUTBERLET 



work was done on a farm at Hardy, Nebraska. A large amount of 

 material was also collected at the poultry farm at the University 

 of Illinois. 



Thanks are due to Professor D. 0. Barto, of the University 

 of Illinois, for giving me the privilege of collecting material at 

 the poultry farm. For other assistance I am indebted to my father 

 and mother, William and Flora Gutberlet, for their untiring efforts 

 to make this work a success by taking records and making collec- 

 tions of material at times of the year when they would not otherwise 

 have been taken. 



I wish to express my appreciation to Dr. Henry B. Ward, at 

 whose suggestion this work was first taken up, for his helpful sug- 

 gestions and criticisms during the preparation of this paper. 



Methods op Technic. In making collections of tapeworms 

 the intestine of the bird was slit open under water and the con- 

 tents removed by shaking gently. The worms are usually attached 

 to the wall and can be easily seen and removed with the aid of a 

 pair of needles. Those that are not attached sink to the bottom of 

 the dish. 



In removing the worms from the intestine it was found best 

 to transfer them directly to fresh water. A weak saline solution^ 

 was demonstrated to be harmful as the worms die in it in a very 

 short time. Tower (1900: 362) found saline solution harmful to 

 cattle cestodes (Monezia). In fresh water, the worms soon become 

 well extended and remain alive and normal for twelve to fifteen 

 hours, or even longer. The worms are best killed in a corrosive- 

 acetic solution and preserved in 70% alcohol and glycerine. For 

 study of structure and accurate diagnosis of species the worms 

 were cut in sections from 5 to 10 microns in thickness, stained in 

 Delafield's or Ehrlich's acid haematoxylin and destained in acid 

 alcohol. 



In order to use house-flies for experimental purposes one has 

 to work out first, methods of keeping them alive. The flies used 

 were kept for experiment in small cages. They demanded a great 

 deal of attention because the slightest disturbance of conditions 

 was harmful. They were fed most satisfactorily on blood, liver, 

 and spleen. It was found that a fly could not live long without- 

 a constant supply of water in the cages. The cages had also to be 

 placed in the sun for a few minutes each morning, and then kept 

 in the shade for the rest of the day, but not in a cool place. 



