62 
liatharine Foot and E. C. Strobell, A Study of Chromosomes etc. 
Plate III. 
The chromosome groups of this plate show in each preparation every chromosome 
of the group. 
Photos 21 to 23. Late prophases of the first spermatocyte mitosis. 
Photos 2A to 29. Metaphase chromosomes of the first spermatocyte mitosis. 
Photos 30 to 35. Metaphase chromosomes of the second spermatocyte mitosis. 
Photos 36 to 38. Three groups of spermatogonial chromosomes. 
Photos 39 to 43. Five groups of chromosomes from what is presumably a male 
embryo. It was removed from the egg three days after deposition. 
Photos 44 to 45. Two groups of chromosomes from the ovarj’. 
Photo 46. An early prophase of a group of chromosomes from an embryo 
removed from the egg three days after deposition. 
Photos 47 to 53. Seven groups of chromosomes from what is presumably a 
female embryo. The same embrjm from which the prophase of photo 46 was taken. 
Plate IV. 
The preparations of this plate demonstrate the presence of a marked chromatin 
nucleolus in the growing oöcyte, a structure which appears to be t\’pical of Euschistus 
crassus, but one we have been unable to differentiate with the same technique, in any 
of the other Euschistus species we have studied. 
Photo 54. A young germinal vesicle with the chromatic net-work just beginning 
to be differentiated and the chromatin nucleolus still very small, x 1000. 
Photos 55 to 59. Germinal vesicles in later stages of the growth period. In each 
the large chromatin nucleolus is clearly differentiated. x 600. 
