MENDELIAN RATIO AND CHROMOSOMES 493 
thin thread joining the two parts. A decided difference in the 
size of the two dyads proclaims this as the tetrad formerly 
united to the accessory. 
While all the other tetrads are made up of quantitatively equal 
parts and follow the typical Orthopteran plan of division (longi- 
tudinal in the first spermatocyte and transverse in the second) 
already worked out for Brachystola by Sutton, this tetrad divides 
transversely in the first spermatocyte, as is evident from an exami- 
nation of the prophases, where it is united with the accessory so 
that the longitudinal split between the chromatids of the tetrad 
corresponds with the division between the chromatids of the 
accessory. This involves the further exception that the spindle 
fibres must become attached to the free instead of the synaptical 
ends. The unequal size of the two dyads allows no mistake on 
this score; otherwise, we should have one large and one small 
chromatid passing to each second spermatocyte (a condition 
which Wenrich has actually found in a nearly related genus, 
Phrynotettix). Here we see that although the connection with 
the accessory is lost, this tetrad is still in the line of behavior de- 
scribed by McClung (’05) for the multiples of Hesperotettix and 
Anabrus, which remain associated with the accessory throughout 
the maturation divisions and are made up of quantitatively equal 
parts. 
_ Three hundred cells were drawn under the camera lucida to de- 
termine the distribution of these dyads in relation to the accessory. 
Of these, 228 show the accessory and tetrad in the same section, 
and as this does not include any case in which there is any uncer- 
tainty, either in regard to the pole for which the accessory is 
destined or where there is the possibility that the dyads do not 
reveal their true size, there can, I think, be no reasonable doubt 
of the results. In 107 cells the smaller dyad was going to the 
same pole as the accessory, and in the remaining 121 the larger 
dyad occupies this position. In the other 72 the accessory and 
tetrad are in different sections, but great care was used to make 
sure that there was no mistake in identifying the cell or in labeling 
the drawings. The smaller is accompanying the accessory in 39 
of the cells, and the larger in 33. This practically agrees with 
