74 EDMUND B. WILSON 
EXPLANATION OF TEXT FIGURES 
Figures 1 to 9 are from camera drawings, and are not schematized except 
that in a few instances the chromosomes have been artificially spread out in a 
series in order to facilitate comparison. Figs. 2 k-l are somewhat more enlarged 
than the others. In all the figures d denotes the double chromosome or ‘d-chro- 
mosome,’ s the small chromosome, X the large idiochromosome and Y the small. 
al ie {| abe a a, PAN 
WY ¢ 4d 
@@, 
e .@ 
ee h 
@e @, 
e, Se 
Sees: / 
Fig. 1 Thesecond spermatocyte-division in Nezara viridula. a-d, metaphases 
in side view; e-g, anaphases; h, 7, polar views of two sister-groups, middle ana- 
phase, from the same spindle and in the same section. 
tion, appears in several other pentatomids (e.g., in Euschistus, Coe- 
nus and Mineus). But Nezara forms no exception to the rule that 
the central chromosome is the idiochromosome-bivalent. In N. 
viridula this is immediately apparent in side views (often also in 
polar views) where the central chromosome is seen to consist of two 
very unequal components, the smaller being not more than one 
fourth or one fifth the size of the larger (fig. 1 a-c). In the ana- 
phases these separate and pass to opposite poles, while all the others 
divide equally (fig. 1 e-g). Polar views of middle or rather late 
anaphases, when both daughter-groups can be seen superposed 
in the same section, clearly show the marked difference of the 
two groups in respect to the idiochromosomes (fig. 1 h-7). All the 
facts are here so nearly similar to those seen in Euschistus or 
Lygaeus as to require no further description. 
