402 MITCHEL CARROLL 
the upper and lower angles of the proximal or synaptic end. It 
is when this occurs, no doubt, that the element divides, as. it 
does occasionally, in the first maturation mitosis (pl. 11, fig. 110 
s; pl. 12, fig. 111,s). Thus, for this element, the first maturation 
division is usually reductional, but may be equational. In this 
behavior it differs from the unpaired supernumeraries described 
by Carothers (17) in Trimerotropis and Circottetix, Wilson (’07, 
10) in Metapodius and Banasa, and Robertson (17) in Tetti- 
gidea. In Trimerotropis, Circottetix, Tettigidea, and Banasa 
the supernumeraries are reported to pass always to one pole 
undivided in the first division, but to divide in the second. In 
Metapodius the unpaired elements invariably divide in the first 
and not in the second. Hence the camnulan extra dyad re- 
sembles more in its behavior at this stage the supernumeraries 
in Ceuthophilus and Diabrotica, which, according to Stevens (’08, 
"12 a, ’12b), divide indifferently in the first or second. The un- 
paired extra element when it fails to divide in the first mitosis 
segregates quite independently of the accessory. In figures 105 
and 106 it is passing to the same pole as the accessory, in figure 
107 it has gone to the opposite pole. It is a matter of chance 
whether it goes to one pole or the other. In this respect it is in 
agreement with most of the unpaired elements mentioned in the 
literature. 
Every dyad present in a second spermatocyte cell divides at 
mitosis. Hence, although it is not possible to state positively 
that a particular element in a given second spermatocyte cell 
was an unpaired dyad which passed into one daughter cell undi- 
vided at the first spermatocyte mitosis, it is certain that all such 
dyads do divide at the second mitosis. Supernumerary dyads 
in second spermatocyte metaphase and anaphase are indicated 
by the letter s in figures 37, 38, 134, and 139. 
When an extra dyad divides in the first mitosis it reappears 
in the succeeding metaphase of each daughter cell as a monad (pl. 
12, figs. 114 and 117, s). In the anaphase of the second mito- 
sissuch a monad passes undivided into one of the daughter 
spermatids. 
