474 D. H. WENRICH 



II. OBSERVATIONS 

 A. Chorthippus (Stenobothrus) curtipennis 



a. Introductory statement. Chorthippus (Stenobothrus) curti- 

 pennis belongs to the sub-family Truxalinae of the Orthopteran 

 family Acrididae. The material from which nearly all the draw- 

 ings were made consists of a single smear prepared during the 

 summer of 1914 at Woods Hole, Mass., near which place this 

 species was abundant. Through the kindness of Professor 

 McClung I was afforded facihties for preparing and staining 

 cytological material at that time. The smear was fixed in 

 Flemming's stronger solution (at a temperature of about 4°C.). 

 One part was stained with Zwaardemaker's safranin, the other 

 with Heidenhain's haematoxylin. Figures 12, 13, and 14, plate 

 3, are from sectioned material, fixed in cold Flemming's fluid and 

 stained with Heidenhain's haematoxylin. 



While- this material was studied some during the summer of 

 1914 and at Harvard University during the winter of 1914- 

 1915, it was carefully re-examined in 1915-1916 at the Univer- 

 sity of Pennsylvania and again at Woods Hole during the sum- 

 mer of 1916, when most of the drawings were made. I am in- 

 debted to the University of Pennsylvania and to the director 

 of the Marine Biological Laboratory for facilities for pursuing 

 this study at Woods Hole. 



Although material from a number of individuals was studied, 

 nearly all the drawings are made from a single smear derived 

 from one animal as stated above. It was deemed desirable to 

 represent conditions from a single specimen in order to avoid any 

 possible confusion arising through individual variations, since 

 recent studies on such forms as Phrynotettix, Trimerotropis, 

 Hesperotettix, etc., have shown that individuals within a species 

 may vary as to certain features of their chromosomal constitu- 

 tion, but the conditions in each indi\ddual remain constant. In 

 the second place, a smear was used in order to insure the pres- 

 ence of whole complexes in each cell and thus to avoid the diffi- 

 culties incident to the study of sections, where most of the cells 

 are cut and distributed into two or more sections with frequent 



