266 KANSAS UNIVERSITY SCIENCE BULLETIN. 



is one of size. The importance of the discovery of the multiple 

 chromosome is very evident: the elements composing it can 

 be followed through the different species without the shadow 

 of a doubt, which is most important in determining its bearing 

 on heredity.* 



The crying need just now is for a better understanding of 

 the chromosome complex, not only of one species but of many 

 species of a genus, so that careful comparisons can be made. 

 This is the first step toward a correlation of chromosomes and 

 body characters. If chromosomes are definite masses endowed 

 with the transmission of characteristics, then the complex 

 should not differ greatly in the various species of a genus. 



This paper is the first of a series which will have for its ob- 

 ject the investigation of the chromosome complex of the genus 

 Melanoplus, and forms part of a plan of investigation into 

 the acrididean complex which has been outlined by Dr. C. E. 

 McClung. The genus Melanoplus is a large and variable one, 

 while Hesperotettix is small and well defined. Since these be- 

 long to the same group, the Melanopli, the nature of the com- 

 plex may be correlated with the generic variations. 



A species of Melanoplus has been investigated by Wilcox 

 ('95), but his aims were somewhat different from those of the 

 present paper, as were his results. The old idea was that an 

 understanding of the complex of one species meant not only 

 knowledge of the whole genus but of practically all animals. 

 Thus, believing that the first division in Melanoplus femur- 

 rubrum is transverse, he concludes that this method of division 

 is general. In such a well-defined group as Hesperotettix 

 (McClung, '05) it was found that what is true for one spe- 

 cies may be true for all ; but in Melanoplus, a large and variable 

 group, there are probably variations to be found in size, in 

 chromosome grouping, and in various other respects. The ob- 

 ject of this series is to study and compare these variations. 

 As to division, however, no discrepancies have been discovered. 

 McClung found, contrary to Wilcox, that the first division in 

 Melanoplus femur-rubrum is longitudinal, and my investiga- 

 tions on M. bivittatus supports this view. 



* Since this paper was written, Doctor Wilson ('07) has found multiples in the 

 Hemiptera. 



