lee 
THE MEIOTIC PHENOMENA IN BLAPS Gi 
inasmuch as on these differences hinges our whole interpretation 
of the facts. 
We might adopt the view that the four chromosomes entering 
one of the secondary spermatocytes constitute a multiple X- 
_ chromosome acting like a unit, while the M-chromosome passing 
to the other spermatocyte is the so called Y-chromosome; but 
this encounters serious difficulties. Not the least of these is that 
we have no conclusive proof that the chromosome thus segregated 
from the complex is constantly one and the same individual. 
In the event of marked differences between the M-chromosomes, 
it would be easy to decide on this point, but the observed differ- 
ences are far from being constant. Without denying the above- 
suggested possibility, we must not overlook another one, namely, 
that the distribution of the M-chromosomes among the spermato- 
cytes may be a matter of chance, as proved for heteromorphci 
pairs of euchromosomes in some Orthoptera (Carothers, 713, 717; 
Voinov, 714; Wenrich, ’14, ’16; Robertson, 715). 
This interpretation is strengthened to some extent by the 
behavior of the components of the X-complex during the growth 
period. We cannot understand at present why one of the chro- 
mosomes is condensed, showing all the typical features of the 
sex chromosomes of other animals, while the others closely re- 
semble the conditions of the euchromosomes. Wherever it has 
been possible to trace the history of a double or multiple X- 
chromosome, it appears—with the possible exception of Ascaris 
lumbricoides (Edwards, ’10) and Ascaris incurva (Goodrich, 716) 
—as a group of massive bodies throughout the postsynaptic 
stages, whether or not associated with a Y-chromosome. It is 
found in this condition in the spiders (Berry, ’06; Wallace, 05, 
709; Painter, 714) and in the complexes of some Hemiptera— 
Fitchia, Rocconota, Conorrhinus, Prionidus, Sinea and Acholla 
(Payne, 709, ’10). In other species they fuse into a single mass 
in which no individual chromosomes can be detected, as occurs 
in Galgulus (Payne, ’08), Syromastes (Gross, ’04; Wilson, 711) 
and Ascaris canis (Walton, 716). Furthermore, the Y-chromo- 
some, when present, appears always asa massive body. The only 
exception to this rule is, if I remember correctly, the case of the 
