Kansas IInivehsity Science Bulletin. 



Vol. IV, No. 13. SEPTEMBER, 1908. 1 vJL'^xVnoTs' 



THE CHROMOSOME COMPLEX OF SYRBULA 



ADMIRABILIS. 



BY W. R. B. ROBERTSON. 



(Contribution from the Zoological Laboratory, No. 180.) 



Submitted In partial fulfillment of the requirements for the degree of Master of Arts. 



Plates XVIII to XXII. 



THIS paper is the first of a series by the author, and one 

 of a larger series from this department, in which will 

 be recorded the attempts to find the relation existing 

 between body characters and germ-cell structure. Much de- 

 tail has been necessary in this preliminary work in order to 

 lay a foundation for future comparisons between the four 

 species of Syrhiila, and also to clear up the misunderstand- 

 ings concerning the phenomena of maturation in this genus 

 that have been brought about by Montgomery ('05) in his 

 investigations upon Syi^bula acuticomis. This latter purpose 

 is of particular importance since Montgomery's findings form 

 the only recorded exception to the rule of uniformity in the 

 entire Acrididsean family. 



Syrbula admirabilis belongs to the short-horned grasshop- 

 per family Acrididse and to the sub-family Truxalinse. It is 

 found most commonly in the central part of the United States. 

 The three other species, acuticomis, fusca-vittata, and monte- 

 zuma, are southern in their habitat, occurring chiefly in the 

 southwestern states and northern Mexico. 



The material for these observations was obtained in Dick- 

 inson county, Kansas, during July, 1906. Flemming's fluid 

 was used for fixation. Heidenhain's iron-haematoxylin was 

 found best for staining during the metaphase of mitosis and 

 Flemming's tricolor the most desirable for all other stages, 

 especially where it was desired to distinguish between the ac- 

 cessory chromosome and the structures commonly called nu- 



(275) 



