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STUDIES ON CHROMOSOMES 
VII. A REVIEW OF THE CHROMOSOMES OF NEZARA; WITH SOME 
MORE GENERAL CONSIDERATIONS 
EDMUND B. WILSON 
From the Zoélogical Department, Columbia University 
NINE FIGURES AND ONE PLATE 
CONTENTS 
(ADO) oC CLOVE! Scere clos Oe ge i OME err CARA ale Berek oe Ete Sin so em (ol 
ID SSSR OMIN Gein eS cc gies oD ae ee Oe OC Gos aed tans bone 5 Oa ae 73 
1 The second spermatocyte-division in Nezara.......................... 73 
ft Ne MCtOC ArOMOsOMes.....< ...: i... 0. See eee ne ea ee ho 73 
bethevdouble:chromosomie:... \s. \532 cee oo ented ee peer we 
AeolheaiEstspermatocyle=GivisiOn .-.ic, i dacs save eel ee nae) eee ee eee 78 
3 The growth-period and spermatocyte-prophases....................... 80 
aU he diploidhchromosome-groups .-.....:: “Sd. see eA eee ee 83 
(Glemer al eet Pee e eee RS bes erie cid Boog) avd SO ee See tae nb 84 
eM DHEVLCIOC HT OMOSONIGS,. §.).)< 05 .:.« Sis.d cj 2 ole eek) ake eee een OU. ph be oc 84 
Ba Composlinoneanaduorioin) Ola tine: \eys= Deligianni 85 
be Maditicattens:of the X-element,....../.0-4. ccc pe eee sya wicicns «ok 88 
Groex<limmttcdehered tty J:.... <0). 22a eee eee eae eee 94 
d- secondary, sexual characters’. >. .\/.4 22 ee eae ans ated ke 99 
6 Modes in which the chromosome-number may change.................. 99 
OCIS OM mower een ekg. brs... 95 2ye.<s ae ee 15 0 ae 105 
INTRODUCTION 
In the first of these ‘Studies’ (05a) I deseribed the idiochromo- 
somes (X and Y-chromosomes) of Nezara hilaris as being of equal 
size in the male, and reached the conclusion that in this species 
no visible dimorphism appears in the spermatid-nuclei. In my 
third ‘Study’ (06), after examination of the female diploid groups, 
this species was assigned a unique position as the single then 
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