186 KANSAS UNIVERSITY SCIENCE BULLETIN. 



The value of comparative cytological study was urged by 

 Vom Rath (25) , and its importance in relation to the accessory 

 chromosome and the maturation mitoses received recognition 

 in both my earlier papers (16, 17) . Recently Montgomery (15) 

 has added his influence to the movement. 



The observations upon which the present paper are based 

 were originally made upon Xiphidium. The cells in this genus 

 are, unfortunately, small in size, and much difficulty was ex- 

 perienced during the early work in getting clear images. This 

 embarrassment was further increased by the large number of 

 chromosomes and their habit of compact arrangement. Later 

 it was found that species of Anabrus, Orchesticus, Microcentra and 

 Scudderia have cells much better adapted for study, and because 

 of this they have been largely utilized. The account which fol- 

 lows is therefore based upon a study of all these genera, and is 

 considered representative of the family. The accompanying 

 figures are principally from Orchesticus, since the number of 

 stages represented exceeded those in material derived from 

 other genera. I am indebted to a friend and former student, 

 Mr. W. S. Sutton, now of Columbia University, for a generous 

 supply of Orchesticus and Anabrus testes from his collections. 



II. TECHNICAL METHODS. 



For the fixation of material used in these studies, it has been 

 found that the osmic acid mixtures of Flemming and Hermann 

 are the most generally applicable and are productive of the best 

 results. In connection with these, however, Gilson's aceto- 

 nitric-sublimate mixture has been tried, and frequently affords 

 an excellent fixation. Extensive shrinkage in the melted par- 

 affin is sure to follow the use of sublimate mixtures unless 

 celloidin is used to support the soft tissue. This double infil- 

 tration of celloidin, followed by paraffin, has been found the 

 best method of securing clear and accurate figures, for, because 

 of the lessened shrinkage, the elements are not crowded together 

 and rendered indistinct. This circumstance is particularly for- 

 tunate in the case of the Locustid cells, where the nuclear ele- 

 ments are so numerous and crowded. 



The stains employed are the iron-hsematoxylin of Heidenhain 

 and the safranin-gentian violet-orange combination of Flem- 

 ming. For general purposes, nothing excels the lnpmatoxylin 



