AUTHOR S ABSTRACT OF THIS PAPER ISSUED 

 BY THE BIBLIOGRAPHIC SERVICE, MAT 23 



GENETICAL BEHAVIOR OF HETEROMORPHIC HOMOL- 

 OGOUS CHROMOSOMES OF CIRCOTETTIX 

 (ORTHOPTERA) 



E. ELEANOR CAROTHERS 



Department of Zoology, University of Pennsylvania 



FIVE PLATES (tHIRTY-FIVE FIGTJRES) 



CONTENTS 



Introduction 457 



Material and methods 460 



Observations 461 



1. Description of general chromosomal conditions in the species 461 



a. Typical conditions 461 



b. Methods of transformation of tetrad no. 7; E-shaped tetrads 462 



c. An octad multiple 464 



d. Differential frequency of atelomitic condition of the three critical 



pairs 465 



2. Description of chromosomal complexes involved in specific matings... 466 



a. Mating no. 2, plate 1 466 



b. Mating no. 13, plate 1 468 



c. Mating no. 5, plate 2 468 



d. Mating no. 14, plates 3,4 469 



e. Mating no. 17, plate 5 469 



Discussion 470 



Literature cited 473 



I. INTRODUCTION 



"Science begins with naive, often mystic conceptions of its 

 problems. It reaches its goal whenever it can replace its early" 

 guessing by verifiable hypotheses and predictable results, Mor- 

 gan ('16). The facts herein presented have been so thoroughly 

 guessed as to cause almost a feeling of apology for presenting 

 them. Since Mendel's laws became generally known in 1900 so 

 many points have been brought out showing that the behavior 

 of the chromosomes during maturation and fertilization pro- 



457 



