58 
Franz Schräder 
process. It need only be pointed out that if the chromosomes of the 
massed group have no homologous mates, the same is true also of the 
remaining chromosomes, and that this is therefore no reason why either 
group should evolve in advance of the other. 
The meiotic stages of the male germ cells of Pseudococcus bear some 
points of striking resemblance to the same phases in the haploid males 
of various Hymenoptera. In both cases there is an equation division. 
The reduction division in Hymenoptera is höwever eliminated or becomes 
abortive, simply because no chromosomes are available for one of the 
two poles. That all the chromosomes go to one pole may possibly be 
explained on the ground that like multiple X chromosomes of Reduviidae 
OT Ascaris there is a certain tendency for all the chromosomes to act as a 
unit and not independently. The absence of homologous mates to each 
of the chromosomes in haploid males is also attested by another striking 
feature. In the honey bee Meves (’07) points out that for the abortive 
reduction division a complete spindle is not formed at first. Instead, all 
of the fibers originate from one pole and some of them connect with the 
chromosomes, so that only a half spindle is formed. Later on, the 
opposite pole also sends out fibers, but generally more or less irregu- 
larly. In Vespa (IVIeves and Duesberg, ’08) such a liaü spindle is 
formed and never completed. In view of the well established dose 
relationship between spindle fibers and chromosomes, irregularity or 
failure of the fibers to form in absence of the latter is not altogether 
surprising. 
In Pseudococcus a haphazard distribution of chromosomes in reduc- 
tion is also prevented. The perfectly definite distinguishing character- 
istics of each of the two chromosome groups make it possible to follow 
them through the entire division and it is plain that the clumped group 
acts as a unit and that all its members go to one and the same pole. The 
problematic nature of this tendency to clump and undergo the various 
phases together has already been discussed and I need only repeat that 
any explanation is more or less speculative. The chromosomes of the 
loose group then always go to the opposite pole. Another remarkable 
resemblance to the reduction in Hymenoptera is found in the formation 
of the spindle fibers. The massed group of chromosomes has its fibers 
formed in a perfectly normal manner. The spindle fibers for the loose 
group are however formed later and in an irregulär manner, and although 
the members of this group all go to the pole opposite to that just men- 
tioned, there is a very noticeable lack of coordination among them. They 
are prone to straggle out and lag on their way to the pole. 
