12 ILLUSTRATIONS 



70. Cross Between White-Eyed Female and a Red-Eyed Male of the 



Vinegar Fly 169 



71. Cross Between a Yellow White-Eyed Female and a Wild-Type 



("Gray"), Red-Eyed Male 171 



72. The Results from the Reciprocal Cross of That Shown in Fig. 71 . . . 173 



73. Scheme Showing the Relation of the Sex-Chromosomes of the Moth 



in Sex Determination 174 



74. Cross Between Abraxas lacticolor Female, and Grossulariata Male .... 175 



75. Cross Between Abraxas grossulariata Female and Lacticolor Male. . . 176 



76. Cross Between Barred Plymouth Rock Male and Black Langshan 



Female 178 



77. Scheme Showing the Transmission of the Sex- Linked Characters .... 178 



78. Cross Between Black Langshan Male and Barred Plymouth Rock 



Female 178 



79. Scheme Showing the Transmission of the Sex-Linked Characters 



Shown in Fig. 78 179 



80. First and Second Spermatocyte Divisions in the Bee 181 



81. First and Second Spermatocji;e Divisions in the Hornet 182 



82. Life Cycle of Phylloxera carycecaulis 182 



83. Extrusion of the Polar Body from a Male-Producing Egg 183 



84. First and Second Spermatocyte Divisions in the Bearberry Aphid 184 



85. Hydatina senta: Adult Female, Young Female Soon After Hatching, 



Adult Male, Parthenogenetic Egg, Male-Producing Egg, Resting 

 Egg 186 



86. Diagram Showing How a Continuous Diet of Polytoma Through 



Twenty-Two Months Yielded Only Female-Producing Females. . . 187 



87. A, Gynandromorph of Drosophila melanogaster, that was Female on 



Right Side and Male on the Left; B, Female on the Left Side 

 and Male on the Right 190 



88. Diagram Showing EHmination of X' at an Early Cell Division 191 



89. Caterpillars of the Silkworm Moth 192 



90. Diagram Illustrating How a Heterozygous Egg With Two Nuclei 



Fertilized by Two Sperms Might Produce a Gynandromorph like 

 that Shown in Fig. 89 193 



91. Scheme Showing the Transmission of a Lethal Sex- Linked Factor 



in an X-Chromosome 199 



92. Normal Female and Male Groups of Chromosome of the Vinegar 



Fly 200 



