THE SPERMATOCYTIC DIVISIONS OF LEPTOCORIS 



H^MATOLOMA. 1 



LELIA T. PORTER. 



INTRODUCTION. 



The spermatogenesis of Leptocoris hcematoloma (family Corei- 

 dae) very closely resembles that of Anasa tristis, as described by 

 Paulmier. During the past few years it has been used extensively 

 here in the course on cytology to demonstrate the behavior of 

 the X-chromosome. As a matter of record, it seems worth 

 while to give a very brief account of the spermatocytic divisions. 

 Furthermore, the material is very fine for the study of tetrad 

 formation, and it is hoped later to publish an account of this 

 process. 



The material on which these observations were made was 

 collected in November and December, 1914, on the plant Cardio- 

 spermum halicacabum, the balloon vine which is very common 

 in this vicinity. It may be of interest, however, to know that 

 this is the only plant on which we have found this bug. The 

 testes, which are large yellow pear-shaped bodies located at the 

 base of the third pair of walking legs were dissected out in 

 Ringer's solution and fixed immediately in Bouin's fluid. They 

 were stained with iron hsematoxylin and counterstained with 

 eosin and light-green. Other fixing agents were used, but this 

 proved to be the best. 



The material is excellent for the study of spermatogenesis, 

 as the chromosomes are not numerous, and vary greatly in size. 

 It is possible to follow accurately the courses of the smallest, 

 largest and accessory chromosomes throughout their entire 

 history. 



The spermatogonial complex of Leptocoris hcematoloma consists 

 of thirteen chromosomes (Figs. I and 2). These vary in size, 

 but can be classified in three groups. The members of two pairs 



1 Contributions from the Zoological Laboratory of the University of Texas, 



No. 138. 



316 



