Kansas IInivehsity Science Bolletin. 



Vol. II, No. 11. MARCH, 1904. I v?L*''^xipNJfT, 



Vol. XII, No. 11. 



THE FUNCTIONS OF THE NERVOUS SYSTEM, WITH 



SPECIAL REGARD TO RESPIRATION, 



IN ACRIDID5;. 



BY HENRY Z. EWING. 

 From the physiological laboratory of the University of Kansas. 



TN my experiments I have not confined myself to any one species of 

 -■- the Acrididae, but have iised any of the common ones that could 

 be easily obtained, especially different species of the grasshoppers, 

 Melanoplus differ entialis, Dissosteira Carolina, Melanoplus femur 

 rubrum, and Brachystola magna, the latter being an especially good 

 species for experimentation, because of its size. I have not noticed in 

 results of experimentation in the different species any differences 

 that might not have been observed in individuals of the same species. 



Of the literature bearing upon this subject, Bethe's work^ is per- 

 haps the most important. I was able to corroborate many of his ob- 

 servations on the grasshopper, and with abundant material, while he 

 had but few animals to experiment on. 



My work is not all new, yet I think those facts which I have been 

 able to add to those previously determined, justify me in offering this 

 paper for the consideration of those interested in insect physiology. 



Before proceeding with my subject proper, I shall briefly de- 

 scribe the respiratory and nervous systems of the grasshopper, 

 in order to make my paper intelligible to those unacquainted 

 with the anatomy of this insect. The three principal parts of 

 the respiratory apparatus are the spiracles, air-sacs, and tra- 

 cheal tubes. There are twelve spiracles on each side, three tho- 

 racic and nine abdominal. By means of these and the trachea 

 an interchange of air takes place. One very large pair of air- 

 sacs is situated in the thorax and five abdominal pairs arise 



1. Bethe, W. Pflugers, Archiv fur die Gesammte Physiologie, 1897, vol. 68, p. 494. 



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