298 T. H. MORGAN 



eggs. As I have never found winged individuals within the galls 

 the individuals must leave the galls when ready to expand their 

 wings. The origin of the males puzzled me for some timje until 

 I discovered that the stem-mother produces them — at first spar- 

 ingly, but later in larger numbers. The same stem-mother that 

 contains the males also contains young sexual females. She also 

 produces at times both males and individuals that contain par- 

 thenogenetic eggs and embryos with six chromosomes. 



Throughout July and August young galls can always be found 

 at the growing ends of some of the branches. These galls con- 

 tain young stem-mothers, and later some of their progeny. These 

 younger stem-mothers may possibly come from the old stem- 

 mothers, or from belated eggs of the previous year, or from sex- 

 ual eggs of the same year in which they appear. A more de- 

 tailed examination will be necessary to settle this point. 



The sexual eggs begin to pass through their synapsis stages 

 while the young are still present in the stem-mother but even 

 after the young are born and after some of the eggs have left 

 the ovary, eggs at the outlet may show the chromatin contracted 

 at one side. In the male the two reduction divisions may also 

 take place while the young individual is still within the stem- 

 mother, but other individuals do not contain these stages until 

 after the young males have been born. 



Entire individuals were preserved in Carnoy solution, the ab- 

 domen cut into sections, and the sections stained in iron hsemo- 

 toxylin. 



The early spermatogonial cell contains f ve chromosomes (dia- 

 gram 5) . At a later stage I found what seems to be a contraction 

 f gure, plate 2, figures 1 and 2, when the chromatin is shrunken 

 and lies at one side, but as there is nothing specific about this 

 condition it is with some hesitation that I identify it as the 

 synizosis stage. 



The early prophases, plate 2, figures 3, 4 and 5, are interest- 

 ing. The three chromosomes are easily distinguished, even be- 

 fore they shorten into rods. 



Miss Stevens has described a stage that she calls the synapsis 

 stage; but from her figures it seems not improbable that she has 



