1911.]  Gametogenesis of the Gall-Fly, N. lenticularis. 489 
Fig. 19.—Part of an egg in blastoderm stage, showing two groups of vesicular nuclei 
apparently undergoing amitotic division and two smaller nuclei with dark mass in 
the centre. 
Fia. 20 (a, 6).—Stages of apparent amitotic division in blastoderm stage. a, early stage ; 
6, a group of nuclei from another part of the same section. 
Fig. 21 (a, 6).—Division-figures in an abnormal egg. a, division of smaller nucleus 
suggesting haploid type ; 6, division of larger nucleus in the same egg. 
Fie. 22 (a, b).—Nuclei in an egg from same series as fig. 21. a, ordinary nucleus ; 
b, large nucleus undergoing amitotic division or fusion. 
Fie. 23 (a, 6).—a, amitotic division or compound fusion ; 6, single nucleus from same egg. 
Same series as figs. 21, 22. 
Fie. 24.—Group of nuclei (amitosis or fusion). The two nuclei to the left are drawn from 
the next section to the larger group. Same series as fig. 20. 
Fig. 25.—Nucleus showing irregular shape. Same egg as fig. 24. 
Fies. 26, 27.—Haploid divisions (metaphase) in nervous system of male larve (summer 
generation). In fig. 27 each chromosome is seen split preparatory to division. 
Fig. 28 (a, b).—T wo equatorial plates in the nervous system of male larva. a is haploid 
(9, or possibly 10, chromosomes visible) ; 6, diploid (about 16 visible). 
Fie. 29.—Diploid group, nervous system of male larva (same specimen as fig. 28). 
Highteen chromosomes are visible. 
Fie. 30.—Mitosis.of giant nucleus in muscle-cell, female larva, summer generation. The 
figure extends through two sections, only one of which is represented. Less than 
half of the chromosomes are shown. 
