Heredity and sex . ^16 > i6<^ l6 + i6 = 3S^. Fig. 90. — Oogenesis and spermatogenesis in bee. Four upper figures,A-D, show formation of first (A), and second (B) polar bodies. Only innergroup of chromosomes remains (C) to form egg nucleus. Entrance of spermnucleus in D. E shows scheme of these two di\isions involving eight double(82) chromosomes. F, first and second spermatocyte di-visions, the first,a, b, abortive, leading to pinching off of a small cell without a nucleus, thesecond, c, c, leading to formation of a large (functional) and an abortivecell (above). In the gall fly, Neurote
Heredity and sex . ^16 > i6<^ l6 + i6 = 3S^. Fig. 90. — Oogenesis and spermatogenesis in bee. Four upper figures,A-D, show formation of first (A), and second (B) polar bodies. Only innergroup of chromosomes remains (C) to form egg nucleus. Entrance of spermnucleus in D. E shows scheme of these two di\isions involving eight double(82) chromosomes. F, first and second spermatocyte di-visions, the first,a, b, abortive, leading to pinching off of a small cell without a nucleus, thesecond, c, c, leading to formation of a large (functional) and an abortivecell (above). In the gall fly, Neuroterus lenticularis, partheno-genetic females appear early in the spring. Their eggsproduce females and males — the second fertilized eggs of these females give rise the follow-ing year to the spring parthenogenetic females. Don-caster has found that each parthenogenetic female PARTHEXOGEXESIS 177 produces eggs, all of which give rise to females or elseto males. In connection with this fact he finds thatthe eggs of some females do
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Keywords: ., boo, bookcentury1900, bookdecade1910, booksubjectsex, bookyear1913
