I4O ALICE M. BORING. 



All figures were drawn with a camera lucida, 1/12 oil immersion and 12 com- 

 pensating ocular, then reduced in the engraving to four fifths. The drawings of 

 Plates I., II., and III. are all from acetocarmine preparations, but those of Plate 

 IV. are from material fixed in Gilson and stained in iron haematoxylin. 



EXPLANATION OF LETTERS. 

 A the largest chromosome. 



B ~] 



>- = the two chromosomes almost as large as A. 



C 



X the odd chromosome. 



EXPLANATION OF PLATE I. (Philcenus spumarius). 



FIGS. 1-7. First spermatocyte metaphases from seven individuals with dif- 

 ferent somatic markings. All show 12 chromosomes, one largest (.4) and two 

 almost as large (B, C). Most of them show the odd chromosome at one side of 

 the group (X). 



FIGS. 8-9. Metaphases of the secondary spermatocytes, one with 12 and one 

 with ii chromosomes. 



