THE GENETICS OF HABROBRACON JUGLANDIS ASHMEAD 



(1) dorsal, apical end-chamber with' oogonia, 

 followed by (2) masses of nurse cells alternat- 

 ing with (3) developing oocytes each of which 

 is surrounded by follicle cells. In mature fe- 

 males which have fed upon host caterpillars the 

 lower end of each ovariole is expanded into a 

 storage chamber (uterus) in which there are 

 from two to five eggs with chorion and yolk 

 fully developed and with follicle cells still 

 present but with nurse cells gone. In females 

 about to emerge from the cocoon the uteri are 

 small and empty. The first maturation division 

 is initiated before oviposition. Speicher (1936) 

 showed that when the egg reaches the uterus, 

 acquires a chorion, and loses its nurse cells, 

 its nucleus increases in size, and the chro- 

 matin elements appear. They quickly shorten 

 and with the disintegration of the nuclear mem- 

 brane move to the center of the nuclear area 

 and become arranged on a flat metaphase plate. 

 A spindle forms at the same time. The chromo- 

 somes continue to late metaphase stage, and 

 here maturation is stopped until after oviposi- 

 tion. Oviposition will not occur unless the 

 female has fed upon the host caterpillar. With- 

 in the nuclei of the younger oocytes the ear- 

 lier processes of the meiotic pronhase are go- 

 ing forward. 



The genitalia of the male consist of an out- 

 er and an inner pair of claspers and a penis. 

 In normal haploid males the paired, rounded, 

 yellowish testes (about one-fourth millimeter 

 in diameter) are fused and lie dorsally to the 

 intestine in the posterior part of the body. 

 Each gives off a lateral duct which passes 

 around the intcctine and unites with the acces- 



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