THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. X, No. 13.] January, 1917. [^^rxx^§o'f3 



The Chromosomes of Nomotettix. 



BY MYRTLE FRANCES RAYBURN, 



University of Kansas. 



THE Tettigidse are a small, clearly defined group of grass- 

 hoppers known as the "grouse locusts." Nomotettix is 

 one of the twenty-one genera comprising the members of this 

 family found in North America. Of these, the cromosomes of 

 representative species from four different genera, Choriphyl- 

 lum, Acridium, Paratettix and Tettigidea, have been studied by 

 Robertson ('15 and '16) and Harman ('15). Nomotettix will 

 be the fifth genus to be added to this series. 



In his comparative study of the chromosomes of Tettigidse, 

 Robertson found a uniformity of numbers, and to a great ex- 

 tent of size relations throughout nine species belonging to the 

 four genera above mentioned. In the species of Nomotet- 

 tix, cristatus Scudder, which I have here studied, I find the 

 same chromosome numbers and practically the same lengths 

 of chromosomes. 



The individuals used were from material collected near 

 Lowell, Mass. The testes were fixed in Flemming's fluid and 

 stained in Haidenhain's iron-hemotoxylin. Drawings were 

 made with a camera lucida, and are here reproduced at a mag- 

 nification of 2600 diameters. 



The chromosomes of Nomotettix are of the rod-shaped type 

 and are thirteen in number in the spermatogonia of the male. 

 They may be readily arranged in a series of six pairs besides 

 the accessory. There are two large pairs (Nos. 6 and 5), two 

 intermediate pairs (4 and 3), and two smaller pairs (2 and 1). 

 Usually the sex chromosome shows a woolly appearance, mak- 

 ing it easy to distinguish. Its size is third in the series, com- 

 ing between the 2's and 3's (autosomes) . 



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