STUDIES ON THE BIOLOGY OF PARACOPIDOSOMOPSIS 



II. SPERM ATOGENESIS OF MALES REARED 



FROM UNFERTILIZED EGGS. 1 



J. T. PATTERSON AND LELIA T. PORTER. 



In the first paper of this series it was pointed out that the 

 unfertilized egg of Paracopidosomopsis florid-anus produces a 

 polyembryonic brood of males. It is the purpose of this paper 

 to show that the germ cells of such males are characterized by 

 the haploid number of chromosomes. As in many other Hymen- 

 optera, the presence of the half number is due to the fact that 

 in the parthenogenetic development of the matured egg there 

 is no compensatory process for restoring the full number. As a 

 consequence of the reduced number of chromosomes in these 

 males, the maturation divisions are modified in such a way that 

 two, instead of four, spermatozoa are produced from each first 

 spermatocyte. In the somatic cells of these males the haploid 

 number, subject to certain variations, also prevails; but this 

 is a subject that will be considered later. 



MATERIAL AND METHODS. 



All of the material used in the study of spermatogenesis has 

 been taken from animals reared under experimental conditions. 

 It consists of two large broods of larvae and a series of one 

 hundred pupae taken from a mummified carcass of the host. 

 The two larval broods were preserved forty-eight and twenty- 

 four hours, respectively, prior to the time at which pupation 

 w r ould have occurred. The series of pupa stages were preserved 

 at close intervals, beginning twenty-four hours after the forma- 

 tion of the carcass. 



The three broods yielding this material resulted from an 

 experiment designed to determine whether the unfertilized egg 



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

 No. 131. 



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