132 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
is not constituted of homologous simple chromosomes. Aside from 
this there seems to be nothing to contradict the view that the tetrads 
represent the union of homologous paternal and maternal elements.” 
Such unsymmetrical loops always occur in Stenobothrus in the case 
of two of the larger bivalent chromosomes, as has been previously 
described in detail (Cf. Plate 6, Fig. 93). Sutton (:02) states that in 
Brachystola the first division is equational, but does not describe the 
process in detail. In Syrbula there is a prereduction, according to 
Montgomery (:05), and my results are a complete confirmation of his. 
Voinov (:03) has described a post-reduction in Cybister, a coleop- 
teron, but Holmgren (:02), Nowlin (:06), and Stevens (:06*) have 
found a prereduction in various forms of the same group. In the 
myriapods Blackman (:05, :05*, :07) has described a postreduction, 
but the chromosomes in these forms appear to be very unfavorable 
for determining the sequence of the divisions, and I think are suscepti- 
ble of either interpretation. This author lays much stress on the 
fact that in the early prophase the longitudinal cleavage appears 
before the transverse becomes evident and that it is but natural, 
therefore, to believe that the longitudinal division is the first to be 
completed in the two following mitoses. If the two divisions were of 
the same kind, no doubt this would be reasonable, but since they differ 
so fundamentally it is a question if the argument is valid. 
Stevens (:03, :04) has found a prereduction in the spermatocytes 
of Sagitta and a postreduction in the odcytes of the same form, but 
her figures are inconclusive. 
It remains to consider the cases in which two transverse divisions 
have been described for the Orthoptera. Wilcox (95) maintained 
that both divisions are transverse in Caloptenus (Melanoplus), but as 
his results have been generally discredited it is unnecessary to consider 
them here. Apparently Wilcox’s fundamental error was in assuming 
that there are twelve chromosomes in the spermatogonia, whereas 
there are in reality twenty-three, as in the majority of the Acrididae. 
Recently Otte (:06) has described two transverse divisions in Locusta, 
but his results differ fundamentally from those of Wilcox, since he 
believes that neither is a reducing division in Weismann’s sense. 
According to this author the chromosomes conjugate side by side 
during synapsis. Later the double threads thus formed shorten and 
thicken, while the free ends often approach each other and may fuse 
to form rings. ‘Da nun die Ringe durch Umbiegung eines Doppel- 
fadens entstanden waren, so ist die 1. Reifungsteilung eine Quertei- 
lung des urspriinglichen Doppelfadens. Der Doppelfaden war durch 
