CHROMOSOME STUDIES IN TETTIGID^. II. CHRO- 

 MOSOMES OF PARATETTIX BB AND CC 

 AND THEIR HYBRID BC. 1 



MARY T. HARMAN. 



Introduction 2I 3 



Observations 2I 4 



1. Spermatogonial Divisions 2I 4 



a. Chromosomes of CC 2I 5 



b. Chromosomes of BB 215 



c. Chromosomes of BC 2I 



2. Growth Period 216 



3. Spermatocyte Divisions 2I 7 



4. The X-chromosome 2I & 



Discussion . . 218 



1. Synapsis and Heredity 2I 9 



2. Chromosomes in Hybrids 221 



Conclusions : 



Literature Cited 22 3 



Explanation of Plates 22 6 



INTRODUCTION. 



As was stated in a previous paper (Harman '15) the work on 

 the cytological constitution of the germ-cells of Paratettix has 

 been undertaken for the purpose of discovering whether or not 

 the microscope will reveal any differences in the germ-cells of 

 very closely related forms which may be correlated with the 

 differences in hereditary characteristics. Three forms have been 

 considered in this paper; two breeding true to type, BB and 

 CC and their hybrid BC (Nabours '14 and '17). 



In his breeding work with Paratettix Nabours ('17) has con- 

 sidered only the color patterns of the pronota and femora of 

 the jumping legs. He has found fourteen distinct color patterns 

 which behave as a unit and cannot further be broken up. These 

 color patterns he designated as multiple allelomorphs. In most 

 crossings between different pure types the resultant hybrid is 

 readily discernible from either parent. In those hybrids which 



1 Contribution from the Zoological Laboratory, Kansas State Agricultural Col- 

 lege, No. 27. 



213 



