64 J. T. PATTERSON. 



DESCRIPTION OF FIGURES. 

 PLATE I. 



FIG. i. Entire egg from a smear preparation, made 23 minutes after ovi- 

 position. It shows the germinal vesicle (n), the sperm (s) and the nucleolus (no). 



FIG. 2. Entire egg from a smear preparation, showing sperm (s), ist polar 

 body undergoing division (/ p.b.), second polar body (2 p.b.), egg nucleus (n), 

 and nucleolus (no). X737. 



FIG. 3. Metaphase plate of dividing cell from central nervous system of 

 female larva. It shows 16 chromosomes. X3857. 



FIG. 4. Same as 3. X3857. 



FIG. 5. Metaphase plate of dividing cell from central nervous system of male 

 larva. It shows 8 chromosomes. X3857. 



FIG. 6. Same as 5. X3857. 



