494 Alice M. Boring 



five species ot the Membracid^. In the early spermatid, this is 

 the only condensed body distinguishable (Fig. 152), but later when 

 the chromatin becomes more diffuse, it appears that half the sper- 

 matids have another smaller condensed body (Figs. 153 and 154), 

 which is lacking in the other half. This must be the odd chromo- 

 some, observed in the same stages of three species of Membracidae. 

 In a still later stage, when the reticulum is arranged around a series 

 of clear vacuoles, this difference is still to be observed; all the cells 

 have the one large body, but only half have the small chromosome 

 (Figs. 155 and 156). After this, both bodies disappear, the chro- 

 matin reticulum becomes slightly more condensed at first (Fig. 

 157), the nucleus then elongates but keeps the vacuoles (Fig. 158), 

 and finally condenses into the head of the spermatozoon (Fig. 159). 

 The acrosome is differentiated from cytoplasm at the apex of the 

 head. 



Fig. 160 is the spermatogonia! plate of the species with the 

 larger number of chromosomes. It contains 21 chromosomes, 

 four larger than the others, not differing conspicuously in size 

 among themselves [a^, a.,, h^, b.,). The first spermatocyte equa- 

 torial plate has 1 1 chromosomes, and they show the same size 

 relation as those of the other species, two large ones and one small 

 odd chromosome in an eccentric position (Fig. 161). This plate 

 simply has two more chromosomes of intermediate size than the 

 other. The second spermatocyte plates again show the two large 

 chromosomes (Figs. 162 and 163), the total numbers being 11 and 

 10, instead of 9 and 8. 



Diedrocephala coccinea 



A few scattered individuals were found in July m general sweep- 

 mgs, but in August an abundance of material was obtained from 

 the blackberry vines. The spermatogonial plates show 23 chro- 

 mosomes, two larger than the others {a^ and a^ in Fig. 164). In 

 the postsynapsis stage, the odd chromosome is not surrounded by 

 the spireme, as has been the case in the forms described above, 

 but it stands out distinctly by itself m the clear part of the nucleus 

 (Fig. 165). In the rest stage, it is still of the same size and in the 

 same position, although the nucleus grows much larger and the 



