Plate XVII 



10 



Hetero- and Idib-chromosomes in Insects (Hemiptera). (Reproduced, by per- 

 mission of the Editor, from Quart. Journ. Micr. Science, LIX (1914), 

 p. 499.) (1-5) Protenor belfragei. (i) Female, equatorial plate before 

 reduction, two large hetero-chromosomes. (2) Similar group of the male, 

 one large hetero-chromosome. (3) Spindle of second maturation-division 

 of spermatozoon ; large hetero-chromosome below right pole. (4, 5) Two 

 daughter-plates of same division ; hetero-chromosome in group 5. (6-9) 

 Euschistus <variolarius. (6) Female, equatorial plate before reduction ; no 

 conspicuously small chromosome. (7) Similar group of the male ; one 

 very small idio-chromosome. (8) Spindle of second maturation-division 

 of spermatozoon ; large and small idio-chromosomes in centre. (9) Two 

 daughter-plates of same division ; small idio-chromosome in upper, large 

 in lower. (10) Rocconota annulicornis. Side view of equatorial plate of 

 second maturation-division of spermatozoon, showing large idio-chromo- 

 some paired with two small, (i i) Acholla multispinosa, second maturation- 

 division of spermatozoon, showing large idio-chromosome paired with 

 five small, (i-io from WILSON; 11 from WILSON, after PAYNE.) 



