270 THE UNIVERSITY SCIENCE BULLETIN. 



with species of Paratettix. This is to be expected, since ex- 

 ternally the body characters of Nomotettix are more nearly 

 like those of Acridium than of Paratettix. Likewise, this spe- 

 cies of Nomotettix is much farther away from those of Tetti- 

 gidea than from those of either Acridium or Paratettix. Again, 

 this is to be expected from the fact that Tettigidea belongs to 

 an entirely different subfamily, the Batrachidinse. Nomotettix, 

 Acridium and Paratettix belong to the subfamily Tettiginae. 



4. The sex chromosome may be recognized in spermatogon- 

 ia! divisions by its woolly appearance. 



5. The chromosomes of Nomotettix, when compared as to 

 numbers, relative sizes, etc., with those of other genera of 

 Tettigidse, furnish evidence decidedly in favor of the hypoth- 

 esis that chromosomes are individual self-perpetuating ele- 

 ments. 



This work was done under the direction of W. R. B. Rob- 

 ertson. 



June 1, 1917. 



BIBLIOGRAPHY. 



Harman, Mary T. 1915. Spermatogenesis in Paratettix. Biol. Bull., 

 vol. 29, No. 4. 



Robertson, W. R. B. 1915. Chromosome Studies III. Inequalities and 

 deficiencies in homologous chromosomes, their bearing upon synapsis 

 and the loss of unit characters. Journ. Morph., vol. 26. 



Robertson, W. R. B. Chromosome Studies I. Taxonomic relationships 

 shown in the chromosomes of Tettigidae and Acrididae: V-shaped 

 chromosomes and their significance in Acrididae, Locustidae and 

 Gryllidae: Chromosomes and variation. Journ. Morph., vol. 27, 

 No. 2. 



EXPLANATION OF PLATE. 



Magnification at which drawings were made, x 3900. Reproduced 

 here at X 2600. Small arable numerals indicate the autosomes in the 

 order of their size, from smallest to largest. In spermatogonia there 

 are two of each size. The sex chromosome is indicated by an x. The 

 numeral preceding the a- indicates that the sex chromosome in size 

 occurs between the second and third autosomes. 



PLATE I. 

 Nomotettix cristatus Scudder. 



Figs. 1 to 7. Spermatogonia dividing, metaphase stage. 



