A STUDY IN THE GERM CELLS OF LEPTINOTARSA 



SIGNATICOLLIS 



HARRY LEWIS WIEMAN 



From the Hull Zoological Laboratory, University of Chicago 



With Seventy-three Figures 



CONTENTS 



Introduction 135 



Methods 136 



I. The development of the ovary 138 



The cell elements of the ovary 138 



The formation of the egg-strings 149 



The nutrition of the egg 151 



The nurse cells 1^8 



II. The development of the testis 167 



III. The chromosomes 1'^ 



IV. Summary 194 



The ovary 194 



The testis 197 



Amitosis 198 



The chromosomes 198 



Bibliography ^^1 



Explanation of figures 205 



Introduction 



Leptinotarsa signaticollis, a chrysomelid beetle found in the 

 northern and eastern tributary valleys of the Rio Balsas system 

 in Mexico (Tower, '06), is a favorable form for cytological investi- 

 gation, in as much as the long breeding season, the slow develop- 

 ment of the reproductive organs, together with the fact that the 

 insects can be successfully bred and reared in breeding cages, 

 enables one to obtain any stage in development with relative 

 ease. 



JOURNAL OP MOBPHOLOGY. — VOL. 21, NO. 2. 



